I know there will be people in here hating on Creative. Their drivers are half-ass, though I've never had a problem with them. Creative dropped support for the Audigy series under Windows Vista, so the X-FI series is really your only option there. Depending on what features you want, this card may do what you want:
http://www.ncix.com/products/index.p...reative%20Labs
M-Audio cards don't have Vista drivers, but are still great for XP.
AuzenTech is the new kid on the block with excellent feature-sets and excellent drivers. I'd definitely recommend their cards.
http://www.ncix.com/products/index.p...ture=AuzenTech
or (this is out of your price range):
http://www.ncix.com/products/index.p...ture=AuzenTech
Jam it back in, in the dark.