The "Auzentech X-Fi Prelude" was actually one card that I have been looking into as an option, but it is quite expensive compared to the X-Fi.
Will Alchemy work on the Auzentech card so that I can get surround sound in vista with DirectSound?
EDIT: Found the answer to my own question. On another forum somebody posted:
"second deal breaker for me, also is no support for directsound to openAL converter aka Alchemy like product.
I called Auzentech and e-mailed c-media, got the same answer from both places. they will not provide any wrapper to translate directsound to openal in vista."
So looks like the Auzentech card wont actually run Counter-Strike Source in surround sound either