Don't get headsets with multiple "speakers" per ear. And don't fall for those claims about "True 5.1 Channel". If it's 5.1 channels it's 5.1 channels. Same with 7.1 channels, or 2.1 channels, or whatever. No one is more "true" than the other. What distinguishes headphones is their sound signature, not how many channels they claim to have. A good stereo headphone should be able to provide the positioning and vast soundstage needed for these sort of games.
If you're committed to upgrading your setup, I'd buy the sound card first, then buy the headphones.
Edited by mbamg - 7/24/12 at 9:49pm