TRITTON Technologies Inc. :: Gaming Audio
The AX 720 and AX Pro both connect via digital optical for game audio, and usb for chat. Mic and chat volume is adjustable seperately to the game audio.
Tritton AX 720 Headset reviews - CNET Reviews
Tritton AX Pro 5.1 Gaming Headset Headset reviews - CNET Reviews
AX Pro seems like the better choice, slightly more expensive but all the reviews I checked say it has better sound quality.