It's not as cut and dry as a video card though. Framerate is pretty obvious, the perception of "good sound", on the other hand is a bit more subjective.
Also there is more equipment involved....some people have sound cards and talk about how amazing their XFI is with their crappy medusa or creative 5.1 headphones, where in reality modern onboard with a better set of cans or some decent speakerswill be better.
I'm still very noobish but have heard various setups...I've had Sennheiser HD205s for a few years and loved them. They've been driven from amped sources, a XFI, modded XFI, and onboard. They sounded best on the modded XFI and modding it is what got me recently into audio a bit more...
and now I have an external CS4397 based DAC and a little basic headphone amp along with HD 580s and the sound is wonderful....miles and miles away from my setup before.
However, the sound from even my HD 205s and P5Q deluxe onboard was quite pleasing...I was after all listening to music! Even though I am a classically trained musician who began playing the violin at 3 years old ...if a song comes on the radio and even and there's a bit of static and it's terrible radio sound quality int he first place I can still groove to it!
My point is that people seem to get carried away with this stuff.....I mean remember at the beginning of this thread the guy wanted something for his OFFICE computer "to get sound for whenever I might need to listen to something (product CD for business etc)".
and yet some people get on their hobby horses and start recommending sound cards because onboard sound is "terrible" because it doesn't even do "true 16-bit". I don't think he cares if his presentation is in stunning lossless 96kHz sound on a blu-ray.
I mean lots of people listen to internet radio or to 128kbps MP3s but I hardly see anyone encouraging them to listen to at least 320kbps or FLAC rips, when in my experience that really makes quite a difference as well,
especially when coupled with a good sound card or DAC.