As a devoted vst instrument user....(most of my tunes fall into the rock category). I own many different collections. I used Toontrack Superior Drummer 2 for drums, Kontakt for basses, organs, and acoustic/electric pianos, Dimension Pro for strings and assorted synth sounds and Music Lab's Real Guitars.
I use a lot of other libraries like Sampletank, Orangetree, Indiginus, ect....
 
That being said, many of the instruments included in Cakewalk Platinum could replace all of these with the exception of the virtual guitars. 
 
Kontakt, long ago, replaced Sampletank as my go to swiss army knife of sounds. Kontakt's libraries including many 3rd parties, just make mixing a lot easier. The sounds sit in the mix better than most imho.
 
It's great to be able to have so many choices and options....it's  a good time to be making music.
 
 

Marshall

abacab
SampleTank 3.  $199
 
http://www.ikmultimedia.com/products/sampletank3/
 
 

• Over 33 GB of included sounds
• Over 4,000 new instruments with 21 instrument categories covering the entire span of acoustic, electric and electronic sounds
• Over 2,500 drum, percussion and full construction-kit loops played by world-renowned artists
• Over 2,000 MIDI files in all categories
• 25 additional SampleTank 3 instruments collections
• 17 additional Syntronik instruments collections
  

Interesting - I hadn't thought of Sampletank. Sound on Sound describe it as a jack of all trades, but master of none. Is that fair? I do want top quality sounds, which provide a significant upgrade from Dim Pro, which is my go to at the moment.I also see that instruments can't be edited at sample level - I have never done this before anyway, but it might be fun. So I am still leaning toward Kontakt. Opinions welcomed! 

I think that SampleTank 3 has very good acoustic and electric bass and guitar samples.  Also the brass and woodwinds sound very good, and each come in two categories, Classical and Jazz-Pop. Solo and ensemble are available as well.
 
ST3 meets my needs for real instruments, but if you want serious orchestral libraries, you may want to look at the IK Miroslav Philharmonik collection.  Or choose from one of the previously suggested 3rd party orchestral libraries for this purpose.  The ST3 string samples supplied are good quality, but if you get serious, you may want more articulation control for playing.
 
So I feel that ST3 goes way beyond Dimension Pro as far as sampling goes.  And it is multitimbral, like Kontakt, so you can assign multiple instruments slots to MIDI channels 1-16 in one instance of the VST.
 
I love Dim Pro, but it will always be a synthesizer that play samples first, not really a sampler.  It has it's place, but there are better options if you want to add real instrument sounds to your arrangements.
 
Recommend you download and play around with both the free SampleTank CS and the free Kontakt Player.  They both provide a free factory library of included instruments.  Worth having, and you can get a feel for how these work.
 
The free, expandable, full featured SampleTank 3:
http://www.ikmultimedia.com/products/sampletankcs/
 
Free sample player based on KONTAKT 5:
https://www.native-instruments.com/en/products/komplete/samplers/kontakt-5-player/

...Sound on Sound describe it [Sampletank 3] as a jack of all trades, but master of none. Is that fair?

 
I believe that is a fair assessment. Sorry, abacab. If you're getting some use out of it I'm happy for you, but my experience has not been positive at all.
 
SampleTank 2 was a staple for me for years, not because it had great samples (they were mediocre) but because it had an incredible breadth of instrument choices. Coupled with Miroslav and add-on libraries, it was a treasure trove of sounds. We were all very excited when ST3 was announced, and IKM seemed to be serious about enhancing the product to compete with more sophisticated offerings. With no demo available, I bought it on faith. I was terribly disappointed. There are definitely usable instruments in there, but none of them meet the standards of quality we've come to expect from sample libraries of recent years. I tried hard to find uses for it, but never could. I still haven't re-installed it on my new (now over 1 year old) computer, and not just because I was indignant that they wanted to charge me 10 bucks to re-download it. It just wasn't worth the bother.

bitflipper

...Sound on Sound describe it [Sampletank 3] as a jack of all trades, but master of none. Is that fair?

 
I believe that is a fair assessment. Sorry, abacab. If you're getting some use out of it I'm happy for you, but my experience has not been positive at all.
 
SampleTank 2 was a staple for me for years, not because it had great samples (they were mediocre) but because it had an incredible breadth of instrument choices. Coupled with Miroslav and add-on libraries, it was a treasure trove of sounds. We were all very excited when ST3 was announced, and IKM seemed to be serious about enhancing the product to compete with more sophisticated offerings. With no demo available, I bought it on faith. I was terribly disappointed. There are definitely usable instruments in there, but none of them meet the standards of quality we've come to expect from sample libraries of recent years. I tried hard to find uses for it, but never could. I still haven't re-installed it on my new (now over 1 year old) computer, and not just because I was indignant that they wanted to charge me 10 bucks to re-download it. It just wasn't worth the bother.

ST3 is still an affordable upgrade if all you have is Dimension Pro, which the OP mentioned is his goal to upgrade from Dim Pro, to acquire some real instrument sounds.  And I got it for free with an iRig keys controller. 
 
Sure it doesn't hold a candle to $1000 sample libraries that film score composers need, but there are many users out there who are not necessarily ever going to need all that.
 
With all due respect, the only people who seem to trash SampleTank are those who were originally SampleTank 2 users, who feel they got burned on the upgrade.  If you were, you have my sympathies...
 
But be honest,  that it is the company you have a grudge against, and not the product.  ST3 delivers what it claims to just fine!

My vote also for Kontakt, and the many fine libraries that you can use. Many of the Komplete collection is good (although I own, but don't use ,many pieces  of the collection). I am another one of the ST 2 users that has stopped using it over the years. Thanksgiving is almost always a 50% off sale for NI, and that's when I got the full version years ago; I have never regretted it, and now use multiple instances of Kontakt in all of my projects. 

I too was a Sampletank user... I begrudgingly bought ST3 (after waiting for many years) and was very disappointed. While there are some decent sounds I noticed that most of my favorite ST2 sounds didn't port over...(we're talking individual patches not entire banks)....I actually still use ST2 way more often than I do ST3 so that I can access my favorite presets.
 
I also forgot to mention that I love and use Wavestation by Korg. It was very inexpensive and comes with lots of useful sounds in a wide variety of instruments. It is highly programmable too.
 
I will always be grateful to Sampletank for lagging on the release of ST3. To fill the void I bought Kontakt Komplete and rarely looked back....

A lot of good thoughts above... but id be very careful...after spending well over $25K on sample libraries and synths I wasted loads of bucks on stuff I don't use anymore...   EW sucks but composer cloud is a cheap way to see that for yourself... Sample Tank is 2nd tier also. Even the UVI player has mostly 2nd tier crap..except for Bohemian Violin & Cello, which are truly breathtaking!  Wait for the sale on Kontakt! However MOST content packaged with it is also second tier... I use NONE OF IT!
 
If you want a full orchestra, easy to use, from the top developer (Orchestral Tools) get their brand new "Inspire"    http://www.orchestraltool...orchestra_inspire.php.  It craps on dozens of high end libraries, the capsule GUI is super powerful and easy and all the top orchestrators around are flipping out about it! 
 
Then again, head on over to https://sonuscore.com/shop/the-orchestra/
  And take a look at The Orchestra, a revolutionary smart sophisticated yet slam dunk simple system to add amazing orchestral elements to your compositions.  This a breathtaking creation...nothing like it on earth and it just came out! It too runs on the FREE Kontakt player...
Do yourself a favor and watch all the vids...it would take DECADES to learn what you can do and add quickly to your songwriting adventures with TO! Nothing else compares, from a non orchestrator/songwriter perspective
 
And, beyond this i can't emphasize this enough...Save urself a LOT of money and buy OMNISPHERE! The quality and breadth of content across the entire musical spectrum blow all thats been talked about away by MILES! Add a bunch of Pluginguru libraries for cheap [Skippy has oodles of sales and endless hours of super free education vids on his site]. Then, take your time thinking about very good libraries...mostly the new stuff like The Orchestra, OT's Inspire (which run just fine on Kontakt free player) and wait for amazing sales for top notch stuff like Heavyocity, which just had an amazing sale on just exquisitely sampled stuff...once you decide to plung into full kontakt (if u do!)  black Fri is coming up and DO HOMEWORK before u buy!
 
Ultimately u can avoid a costly journey buying all sorts of crap (like I have)...Actually, thats a bit unfair but the fact is things have progressed rapidly in the sampling field and stuff like EW's Orchestrals are cumbersome and hard to use compared to beautifully crafed new stuff like OT's Inspire...so take your time and spend some of it on VIControl, where loads of some of the best composers/songwriters/vendors hang out and discuss such things in detail...
 
Now, back to your first smart purchase... Omnisphere alone blows Kontakt's included libraries and rhythmic multis that'll blow ur mind...it should be EVERYONE'S FIRST PURCHASE... PERIOD! Best all around library on Eaarth! Unbelievably pristine samples wrapped in the most elegant & powerful synth/modulation platform ever created...
 
Get it...
 
Note... for whatever reason hot links are not working at the moment so just Google the guru and omnisphere

In two words, BUY OMNISPHERE....  It is the single most powerful platform on the planet... and will give you amazing stuff... you might not need more for a long time.
 
A lot of good thoughts already shared above... but id be very careful...after spending well over $25K on sample libraries and synths I spent loads of bucks on stuff I don't use anymore...  Given the current products that have come out over the past few years I feel EastWest stuff sucks (I have most of it) but composer cloud is a cheap way to see that for yourself... Sample Tank is 2nd tier also. Even the UVI player has mostly 2nd tier crap..except for Bohemian Violin & Cello, which are truly breathtaking!  I concur with others to wait for the sale on Kontakt! However, I feel MOST content packaged with it is also second tier... I use NONE OF IT! There IS some GREAT content that works just fine in the free Kontakt player and given what you've said, I urge you to try this first as you'll learn Kontakt/routings and get playing with amazing tools for less money immediately.   
 
If you want a full orchestra, easy to use, from the top developer (Orchestral Tools) get their brand new "Inspire"  which runs on the free Kontakt player  http://www.orchestraltool...orchestra_inspire.php.  It craps on dozens of high end libraries, the capsule GUI is super powerful and easy and all the top orchestrators around are flipping out about it! 
 
Then again, you should also head on over to https://sonuscore.com/shop/the-orchestra/
  And take a look at The Orchestra, a revolutionary smart sophisticated yet slam dunk simple system to add amazing orchestral elements to your compositions.  This a breathtaking creation...nothing like it on earth and it just came out! It too runs on the FREE Kontakt player...Do yourself a favor and watch all the vids...it would take DECADES to learn what you can do and add quickly to your songwriting adventures with TO! Nothing else compares, from a non orchestrator/songwriter perspective
 
And, beyond this i can't emphasize this enough...Save urself a LOT of money and buy OMNISPHERE! The quality and breadth of content across the entire musical spectrum blow all thats been talked about away by MILES! Add a bunch of Pluginguru libraries for cheap [Skippy has oodles of sales and endless hours of super free education vids on his site]. Then, take your time thinking about very good libraries...mostly the new stuff like The Orchestra, OT's Inspire (which run just fine on Kontakt free player) and wait for amazing sales for top notch stuff like Heavyocity, which just had an amazing sale on just exquisitely sampled stuff...once you decide to plung into full kontakt (if u do!)  black Fri is coming up and DO HOMEWORK before u buy!
 
Ultimately u can avoid a costly journey buying all sorts of crap (like I have)...Actually, thats a bit unfair but the fact is things have progressed rapidly in the sampling field and stuff like EW's Orchestrals are cumbersome and hard to use compared to beautifully crafed new stuff like OT's Inspire...so take your time and spend some of it on VIControl, where loads of some of the best composers/songwriters/vendors hang out and discuss such things in detail...
 
Now, back to your first smart purchase... Omnisphere alone blows Kontakt's included libraries and rhythmic multis that'll blow ur mind...it should be EVERYONE'S FIRST PURCHASE... PERIOD! Best all around library on Eaarth! Unbelievably pristine samples wrapped in the most elegant & powerful synth/modulation platform ever created...
 
Get it...
 
Note... for whatever reason hot links are not working at the moment so just Google the guru and omnisphere
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Vastman
In two words, BUY OMNISPHERE....  It is the single most powerful platform on the planet... and will give you amazing stuff... you might not need more for a long time.

I must disagree - but not that I don't think Omnispere is pretty amazing.  The OP said his interest was primarily in real instruments.  This really isn't Omnisphere's forte.  Try to find a cello, for example.  Furthermore, although version 2 of Omnisphere opened things up a bit with user importable sounds, those capabilities there are extremely limited.
 
For a decent starting collection of real instrument sounds, but with deep programmability (like Omnisphere), HALion 6 might be worth consideration.  It provides both real and synth sounds.  However, if the synth sounds are of little interest, Kontakt is still probably the best option.  Who knows, one of these days we might even get Kontakt 6 with a much-improved UI and improved ease of programming.

abacab
But be honest,  that it is the company you have a grudge against, and not the product.  ST3 delivers what it claims to just fine!

I have no grudge against IKM. It is the product, not the company. Maybe you've got me confused with cclarry?
 
OK, I'll admit I was put off when they wanted to charge me to re-download ST3. But that criticism was entirely justified, I think, given that no other vendor has ever even thought of doing such a thing.
 
To get back on topic, I agree with Mr. Baer above. Omnisphere is far and away my favorite synthesizer, but if I had to choose just one thing to take to a hypothetical desert island (that somehow had electricity), it wouldn't be Omnisphere. It would be Kontakt.