Also, realize that for $25-40 you can get a toslink-to-coax converter; so you don't need to limit your shopping. That being said the M-Audio's are nice, and most are bit-perfect (assuming you download the right drivers). The Chaintech AV710 (my card) is the least expensive bit-perfect card I know of ($25), but has toslink outputs, so the converter price needs to be added to your math.
A good discussion on this stuff is on headfi.org's "computer-as-source" forum.
Ted