Is the console right next to the PC? I.e. would you be able to connect the console to the soundcard and run the console sound that way?
Reason I ask is if a console has surround sound it's encoded in some way, and speakers can't decode that themselves.. so you either need a module that will decode the surround sound on the speakers, or some PC soundcards will also decode surround.
http://www.hometheatermag.com/xbox/105spherex/
That set has got great reviews and has the decoding built into the speakers so you don't have to have your soundcard decode it.