Turtle Beach - Riviera 5.1 Sound Card. This is a $30 card that has a digital S/PDIF output perfect for plugging into a home theater.
Ironically, the new Creative X-Fi won't work but the older Audigy2 ZS does because it has an SPDIF output in the rear. It lists for $100 and is probably a better choice for compatibility with games. I've used lots of cards and the problem is that Creative Labs really has the most volume so most folks support it the best.
