I'm wondering if anybody could recommend a good, inexpensive sound card for me to use with Sonar X3. 
I've seen a couple of other threads about this, but most people are looking for things that have extra inputs, and that doesn't apply to me.
 
Basically, I just need something that has low-latency and good sound quality.  All of my music is done via a MIDI controller and internal soft-synths like Dimension, EZ Drummer, etc.  I'm not trying to plug in guitars, mics, or anything else, so I really don't need anything that has extra inputs or any other bells and whistles.  I'm a very basic user. 
I used a Sound Blaster X-Fi card in the past, and it was perfectly sufficient for my needs (well, it was after I downloaded ASIO4All), but as I look around various forums now, the general sentiment seems to be "avoid SB like the plague!"  So I don't know, maybe SB has gotten worse?  Are "gaming soundcards" necessarily bad, even if I don't need extra inputs? 
 
(Just to clarify the situation a bit:  I don't even have my computer yet.  Well, I have one, but it doesn't work anymore, so I ordered  new one, along with Sonar X3.  The computer I ordered comes with only "intergrated audio," which I assume won't be particularly good for recording anything, so I'm planning to upgrade it with either an internal PCI-E card, or possibly a USB card.)
 
Any suggestions would be much appreciated, thanks! 
 
 

For what you need a USB audio interface would be fine, you will gain nothing by putting in a card. In fact, you may well be able to use the on board audio, since you are basically only using it for playback, and all the audio processing is being done by the CPU. If your MIDI gear connects via USB, you do not need a MIDI interface either. A Focusrite Scarlett 2i2 might work for you.

+1, if you are using a USB MIDI device and only need playback, you may already have what you need. You may have to play with driver modes in SONAR to get the best response, like WDM or even MME.

I'm using MME on my Dell Inspiron 5748 laptop via midi, to work out beats and other ideas. Works perfectly. No external sound card needed. I use use my 'big' rid to do all the guitar/vox recording/mixing etc.

Thanks, guys!  That's good to hear. 
So I guess I'll just wait until I get my new computer, and test it out with the integrated audio before giving myself a headache trying to figure out upgrades that I might not even need. 
 
(just to be sure I understand correctly:  Putting in a sound card wouldn't make the audio coming from my softsynths sound any better?  In other words, the audio I get from, say, Dimension Pro, will sound just as good with the integrated audio as it would with a sound card?) 
 
 

A sound card or audio interface won't make your existing audio sound any better, no. The tones are entirely generated in the plugin software, and all the card or interface does is route it to your speakers.

Well more accurately, the audio you are sending through your interface (external or integrated) will be as good no matter what interface you use, but it might not sound as good. That is because the electronics in the interface that acts as a transducer and amplifier of the analog data is not identical in all interfaces. So if you had a really "noisy" interface compared to a pristine one, you could tell the difference, just as you could if you used poor headphones or speakers relative to really good ones. But the digital audio data recorded from softsynths in Sonar will be pristine regardless of the interface. For all practical purposes, unless your integrated audio is really lousy, you will probably not notice a difference, and your recordings would be just as perfect even if you were listening to them via a cement mixer, as they stay in the digital realm. The same could not be said if you are recording real world sound via a microphone into Sonar, because analog noise from the interface would be rendered into a digital representation and would taint your recordings.

Focusrite!

Behringer U-Control UCA202

http://www.sweetwater.com/store/detail/UCA202

 
Pretty impressive for the price.

 On board sound plays audio fine. But if you want to record audio get an interface.
I use my laptops On board for my live performances through a PA system. I compared the sound quality to using my interface and found the only small difference was a slight hum. The tonal quality was the same. It's one less thing to go wrong. I've had USB interfaces shut down on me so I'm gun shy. 
There's no need to buy a PCIe sound card anymore, that was bygone days. Only some real high end stuff like Lynx and RME are PCIe. New Mobo sound chips are just as good as a $ 50-$120 SB would have been back when. 
 
And as far as buying any USB audio interface goes, I've seen Tascam interfaces on Musician's Friend for as low as $30. Not sure if that's an improvement over on board, but it would at least look more serious..There's no point in an audio interface that does not include ASIO drivers. Avoid "uses windows legacy drivers" 
A good basic interface with good drivers however will be about $150 and up.