bitflipper
 
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.

Which is why my recommendation to the OP was to check out the free Kontakt Player, as well as the Sampletank CE, to see what he thinks about them.  Kontakt would be the best option if you plan to collect sample libraries.

Bigcat... Zao's guide is very incomplete...and dated... yes, good stuff but wouldn't use it as a buying guide as includes many dated and little of the recent things like inspire  or TO... is newer better? In this case, YES! GUI design, sampling techniques, scripting...all have improved to help make libraries more playable and realistic, less CPU/ram memory/SSD intensive...by average players like me
 
Re Omnisphere vs Kontakt? The free Kontakt  player gets you the orchestrals and O2 gets u the world. Is Kontakt in nearly every orchestrators/songwriters arsenal? Yes, as is O2... Kontakt is a far better sampler but there it ends. My point is you get the high end content that would cost thousands to try and replicate with K (a pretty empty vessel on its own...and yea, komplete/ultimate gets u loads and it's the "wow! Bargain basement effect that's gotten so many of us to buy in but it's all over the place, gui/quality/feature wise AND learning curve is high for all the zillion so so things which aren't  in omnisphere's league.
 
I know there are lots of komplete fans here...heck, I have Kultimate  myself... but the best thing in it,by far, is kontakt however, even here, each library is different, gui wise... not to mention quality and cost...its an endless moneypit for quality stuff
 
Just pointing a few things out to someone who might wanna focus on composing vs endless, "Wtf is this and how do I use it?"s and disappointments...in this regard, O2 excels, as does it's stellar 60 gb library and unparalled effects plus ability to layer/modulate everything with a consistant engine like no other.
 
Omnisphere+inspire+The Orchestra... top notch, state of the art weapons with NO garbage, confusion, wasted $$$/gas regrets...for $1000!  The rest can come later...and itll all be different by then, but that is an immediate arsenal, and when married with all the free Skippy education vids and additional content... heaven...
 
Just offering a contrary pathway not mired in "history" that avoids the endless gas expense, offers the most bang for the buck, modern/efficient/useable GUI's, top notch quality and immediate usefullness to a musician/songwriter.
 
https://www.pluginguru.com/products/
https://www.youtube.com/user/thepluginguru
 
I'll go away now...

bitflipper

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.

Same here, while there are some nice sounds in ST3 I can almost always do better elsewhere. It was a disappointment and I usually look to Kontakt first, then Composer Cloud, UVI and Rapture Pro

Amplitube on the other hand is the biz.

Jordan Rudess is the one who sold me Omnisphere, too. Beware; once you get sucked into the Spectrasonics world, Trillian and Keyscape will also start calling out to you.

Marshall
Just to round this off, I have decided to buy Omnisphere first, and when Kontakt goes on sale (perhaps Black Friday) I'll maybe pick that up too.

I've been blown away by some of the sound demos I've heard of Omnisphere, including a couple by one of my heroes, Jordan Rudess at NAMM.

I know this is somewhat at odds with my emphasis on real instruments in my original post, but I think if I pick up Kontakt as well and add to it if I need to, I'll have most bases covered. I'm not trying to compose a classical score.

I really appreciate all the time folks have gone to in enlightening me in this thread. I've certainly learned tons.

Let us know how you get on with Omnisphere! 
 
I have held off, mostly due to the cost, and that there is no demo version.  But the demo videos do look cool, and a lot of folks seem to like it!

Congrats, Marshall, the best of the best. Now visit PlugInGuru and get some extra kicks.

I took a look at the Groove 3 videos on Omnisphere 2.
 
That is a very impressive browser and search function that Spectrasonics have developed.  I'm sure that is where much of the power for finding and shaping the sound layers you want resides.  The Boolean search "and/or/not" is also very cool!
 
I am sure that many other synths and samplers could create most any single patch layer sound that exists in the Omnisphere library, but what really seems to set it apart is the very efficient workflow for creating layers and multis.  I have been creating layers of multiple synths (internal and external) for quite some time, stacking them in a DAW, and it is one aspect of sound design that can be very rewarding.  But having that ability in a common GUI environment and browser takes it to a whole new level. 
 
Still wish they had a demo version! 

bit, That's all good info and is quite believable, but I can imagine that if Spectrasonics would just assemble a small part of that into a demo package, then they could make believers out of us skeptics.  $500 on faith, I dunno ...

As someone who has composed and produced a lot of music involving synthesis I can offer a different point of view. From a totally synthesist point of view as opposed to someone using a synthesiser in a more traditional rock or pop context. 
 
Every synth has a sonic signature and using one to do many things can suffer from everything sounding like it is coming from just one synth. (software included)  It is better to involve a range of synths in order to get the different sonic signatures and be able to blend them.  Something a single instrument can never do.  I have a large collection of instruments which between them would easily cover the sonic palette that Omnisphere would offer and probably far more in reality.  Instruments like Native Thrill for example. (with its 30 Gig library!)  This is a Cinematic tension instrument and Omnisphere would not even come anywhere close to this.  Others like Prism, Alchemy and Granite and the list goes on.  So I agree with abacab in that with multiple instruments you can basically cover everything and more.  Latest thing for me is PPG Infinite. This is an iOS app only right now but if you have an iPad docked into a quality dock and connected up to your studio it becomes a seriously playable synth.  And it has a sound out of this world.  No samples in sight either.  It also goes into territory I doubt Omnisphere could venture into.
 
Having a range of synths is one of the reasons I have not bought into Omnisphere because I don't feel any real need to.  I am sure it is a fantastic instrument for someone who did not have that much to start with and wanted to get a lot at once it would be an excellent choice.
 
I don't agree with the OP poster getting it first.  It does not have a full range of bread and butter sounds like Kontakt does.  And as pointed out here when he needs a simple cello line he may not find it anywhere in Omnisphere.  (pity considering you have just spent $500!) I think he has been a victim of the hype surrounding it instead of the real need.  A GUI should not matter, it is all about its sound and nothing more.  Any GUI or synths operating system can be gotten around in order to get a job done.  The demos for it may be amazing but you have to ask yourself are you going to produce music exactly like the demos.
 
I have built up the bread and butter sounds myself first before getting into anything other than that and I can assure people that in reality it is those sounds that really get used most often.  In my case anyway it was certainly the better way to go.  Especially from the point of view of doing jobs professionally and getting paid for them. 

Vastman
Yay! Great move... As Fleer noted, avail yourself to the guru's numerous educational vids and pick up some goodies on his next sale...

Enjoy... Smart move

Thanks for originally bringing it to my attention - absolutely thrilled!

Thanks guys I will look into it.  I also have the free Kontakt player and bought quite a few paid for full Kontakt libraries that work fully with it too.  Does that help?  I also have the full version of Prism too. (Reaktor)

If you sign into your NI account and click to buy a Kontakt crossgrade, they will inform you if you already have a qualifying product, and the price you are eligible for.  I see a nice discount in my account.
 
But so far I have resisted falling into this money pit, as I already have over 80 virtual instruments to keep me busy! 

My original Garritan GPO qualifies me, for the NI crossgrade, which was a surprise.
 
Does that mean the $249 crossgrade price will be $125 during their sale (whenever)?
Thanks
Michael

pentimentosound
My original Garritan GPO qualifies me, for the NI crossgrade, which was a surprise.
 
Does that mean the $249 crossgrade price will be $125 during their sale (whenever)?
Thanks
Michael

Sorry, but I think crossgrade (and EDU) discounts do not qualify for sale prices. Still, $249 ain't bad. I think I've paid them more than $700 over the years, $400 for the initial purchase and then 80 to 150 bucks for each of the 4 subsequent versions.