i just got the 24bit SB live card for 30 bucks at my local computer shop (29.00 newegg). its a great upgrade from onboard and i think it has 7.1 support. i highly recommend it as an alternative to a 300 dollar card.
http://www.newegg.com/Product/Product.asp?Item=N82E16829118106
^^ Turtle beach catalina, is probably the best value card. Dont listen to senselss who says the m-audio crap, which is $90 and this is 50. I have this very card myself, I got it to replace my onboard AC'97 audio and get a few more frames in UT2004, and that I did. Plus, it sounds great. Oh BTW, this card IS hardware accelerated. I can prove it by directX sound tests.