I spent a while looking for a sound card, tried a creative (returned shortly after). I ended up sticking with onboard sound and going with those headphones. And I love them, sound great w/out a sound card.
Well, a decent soundcard to start would be the ASUS Xonar DX, which is one of the better all-around soundcards on the market. As for headphones, both Sennheiser and Grado make some very good low priced headphones.
if i were u I'd save a couple bucks and just get the xonar dg. If your asking the question you're probably not sampling above 96Khz. 7.1 surround is isn't a huge deal which u would gain with the dx, (5.1 with the dg) save a couple bucks on the card and get nicer cans imo.