I see. Do you have a suggestion for a decent card? Back in the day I had a Turtle Beach card I loved (that also had a lot of great built in midi sounds), but it's been a while since I bought a dedicated card.
 
I also just realized I was wrong about the Steam Cakewalk price. The $299 price is just for the instruments bundle and doesn't include the actual program. Oops!

Hello Corribus
 
My understanding is that IK Multimedia is getting ready to come out with SampleTank 3, so Sampletank 2 is on sale (as are the other IK soft synths).  The sounds that come with it are generally good, and you can expand it with additional packages.  Check esoundz, as they seem to usually run IK specials.  One caveat is Sampletank 2 is 32 bit, though you can use it with Sonar 64 bit by using jbridge (it's about $20 as best as I remember).
 
Best of luck with your music!

Hello again Corribus,
 
I just checked esoundz (which I should have done before posting) and the Total Workstation package is on sale for $99.  That includes SampleTank 2.5 XL, Miroslav Philharmonik, Sonik Synth 2, SampleMoo, SampleTron, and all 15 of the Xpansion Tank 2 Multi-Sampled Instrument collections.  That is a amazing deal!!

That's a killer deal for sure. It's enough sounds and instruments to keep you busy for a long time.
Getting back to the interface question, here is a link to some offerings from Sweetwater (a company that you will probably come to be familiar with).
http://www.sweetwater.com/c695--USB_Audio_Interfaces/popular/params=eyJkaW1lbnNpb24iOnsiQnJhbmQiOlsiNDI5NDk2NzI2OCIsIjQyOTQ5NjY4NjUiLCI0Mjk0OTY2MjczIiwiNDI5NDk2Njc4MCJdfX0
The link is long because I set some filters. The full list would show units ranging from less than $100(marginal quality) to several thousand $.
I realize this is just a hobby for you, as it is for myself. I have also learned that most worthwhile hobbies tend to be somewhat of a money pit. That said, an interface is probably the best investment you can make. $200-$250 will make a huge difference in your experience.
Your built-in sound chip is fine for simple playback, but can cause problems when it tries to handle the more sophisticated requirements of a program like Sonar.
The software is just part of a system. For it to really sing, you need a proper balance of hardware and software.
Consider for a moment, a race car. You can have the best engine, the best driver, but if you have bad tires, it's all for naught.
I also strongly recommend thinking about getting a MIDI controller. Yes, more money.
But many of the soft synths we have suggested really come to life when you can play them as an instrument rather than punching in notes with the mouse.
I understand that we are suggesting that you spend more than you had anticipated, but for what it's worth, once you get into this, you're going to do it anyway.
Just for fun, here's a little piece that was done with some of the soft synths available to you, DimPro, Sample Tank, and Studio Instruments(Strings). All instruments were recorded real-time with a MIDI controller.
http://www.soundclick.com/player/single_player.cfm?songid=10285834&q=hi&newref=1
 
 

@Jude
 
Thanks for the suggestion, I'll check that out.
 
@RobertB
 
I get what you're saying about investments. However I feel it almost needs to be something I build up to gradually. Otherwise it's like spending money without understanding what I'm spending it on. It's almost like I need to start out simple, then be like, "This is good, but it'd sure be better if I could do this!" and when I buy what I need in order to do that, then I realize it'd also be nice to do this other thing. And so on.
 
With the trial version and the digital piano, I recognized the need for some more instruments (and better versions of some of the ones I had). However, now that you mention it, it may be that it wasn't the instruments so much as the mechanical way they sounded due to entering them with a mouse. I may go back and try playing the notes in and seeing if that makes a difference.
 
Which isn't to say that the interface options you provided me aren't useful. I appreciate the help and will certainly look over them. Most of those don't look like internal components though, so they weren't the simple sound card I envisioned.
 
I think the first step is to buy Sonar and go from there. Rome wasn't built in a day. :)
 
(Nice piece by the way. Enjoyed it!)

Corribus
...I am about to conclude my trial run of Sonar...digging any further than that got me into a confusing world of VSTs...All I really want are some nice instruments and other sound effects...Can anyone boil it down for me, maybe make a suggestion for what might satisfy my needs? It doesn't have to be free, but on the other hand, I don't want to spend hundreds of dollars on these either.

Maybe you are unaware that the Sonar package includes a lot of VST instruments and effects and that these are excluded from the trial version. Don't purchase any extra ones until you have tried these first.

Kev999,
Thanks for the heads up. I was unaware of that and will take your advice. Sorry I never responded, too; was away from the internet for a few days.
 

pls ignore : I'm just posting something here to get rid of the spam header left-over.

tomixornot
pls ignore : I'm just posting something here to get rid of the spam header left-over.

Ditto.

And again...