5.1 is on occasions better for positional sound, like when you play FPS games but nothing else. I bet most people don't even know what they are missing with headsets, when compared to a decent set of headphones.
The only headset I can recommend is MEDUSA NX 5.1, or if you have money to throw around and you don't need 5.1 go with the overpriced Sennheiser PC 360.
Since Oleg showed us how SoW will feature binaural sound, I would go with the stereo headset.