[Proxymanity]

Can anyone of you recommend a good 7.1 external sound card? I was looking at the steelseries' 7.1 USB soundcard and was wondering if that was any good. I know it would be preferable to buy and install a new soundcard in my laptop but then there a chance I'll totally mess things up and also void the warranty on the computer. I'm looking to pair them up with a
ATH-AD700. I want the 7.1 because they would be used for gaming.