Depends on what you want to do.
good quality surround card is soundblaster Live. But you'll need a surround speaker system to take advantage of the surround part of course.
Live X-Gamer or Live MP3 are also great cards for 5.1 dolby sound, but an entirely different sound system is needed. If you just want good quality.....go with the Live Value. $40 and well worth it.
Maybe I should also add Creative to my signature! =)