External Sound Card

I'm thinking of buying a mac to replace my PC, but i'm on the edge because not to long ago i bought a 5.1 Channel Surround Sound Stereo System for my PC. I was wandering what good external sound cards there are that are compatible with mac OS X.

Google is yourfriend

Surround-Enable Your MacBook

Or if you want to spend more

ESI GIGAPORT HD 8-out USB Audio Interface - eBay (item 180317800874 end time Jan-12-09 02:08:37 PST)