And this card supposedly works well in linux
Dynex DX-SC51
Linux seems to really like this card. AC3 and DTS passthrough out the optical jack works perfectly, and I can dump stereo audio into it no problem. I get full 5.1 sound out of the analog jacks too. Haven't tried capture or the headphone jack, mainly because I bought this card specifically for an HTPC.
Which isn't bad, even if you don't attach a $20.00 DB50XG card.... $26.00 is a pretty good price for a Yamaha TG33 with an spdif output, don't you think?