For gaming audio (BF3 etc) i use an internal Soundblaster X-Fi PCIe, then optical out to an external amp for headphones. There are a couple of reasons for doing this vs using an external DAC. Creative will tell you the hardware is optimized for DirectSound, and the X-Fi specifically has 64mb of onboard memory it uses to buffer audio samples. I'm not convinced there is a measurable difference in FPS between that and an ordinary onboard sound card, however i would bet its a lot better at playing multiple sound samples at once vs a DAC connected over the USB bus. Remember its not a constant stream of music like listening to an MP3 file your outputting, its lots and lots of different samples on top of each other in quick succession, very different environment.
Second reason as mentioned above is support for Dolby Surround if you want it (personally i stick with 2 channel stereo on headphones), and EAX environmental effects which as far as i know is a Creative proprietary standard. The end result for me anyway is fantastic 3D positioning, if i hear footsteps in game i know its behind me at 5'oclock and ~10 meters away, a huge advantage IMO.
As for cost, you can grab the X-Fi Titanium on ebay for ~30quid. Current flavor of the month seems to be the Asus Xonar series of cards however i dont have any experience with them. I believe they have a much better amp inside them so far superior if your plugging headphones in directly, some claim to drive high impedance loads but they lack EAX support as far as i know. For listening to Music and watching Youtube i use an external dac, X-Fi is used for gaming only.
I'm one of the few people who bought an original Sound Blaster when they first came out, then a v2, Pro, 16bit, AWE32 (huge mofo with dimm slots), 64, Live!, Audigy, Audigy2, X-Fi, X-Fi PCie, you get the idea. Thing is i wouldn't touch any of the new Z-Series or Recon3D with a 10 foot barge pole, i believe the Xonar series is the way to go if buying new. But for me the X-Fi works perfectly, just dont use the onboard amps to drive headphones directly. Come to think of it i'm really only using it as a DAC.
Edited by mcandmar - 9/25/13 at 7:42am