AuzenTech X-Meridian 7.1 Sound Card
If anyone is looking for an outstanding sounding card for their HTPC this one I can strongly recommend. I installed one recently and I'm very impressed. This card is geared more for home theater than gaming but I'm more into the prior so it fits very well for me. You can change the opamps to your hearts content. I'm currently using the LM4562's (available from Digikey, $5 each) over the stock pieces. If you only use S/PDIF out I would go with a less expensive card. Although it will do Dolby and DTS conversion on the fly if you need it. Where this card shines is through the analog outs, but be beware the sound level is higher then your accustomed to. I did an A/B comparison with the same DVD-A disk, one in the HTPC and one in my Denon 2200 playing at the same time through my Paradigm Studio Reference 5.1 setup.They sound similar in the midrange and tweeter range with a slight edge going to the XM . The bass is where the XM out performs the Denon. It's tighter, cleaner and has more thump, it was quite obvious, and yes I did adjust the sound levels for an accurate comparison.
Highly recommended IMHO.