First off, do you own a sound card ? Because if you don't, unless you decide to buy a USB Headset, it's useless to pay for a high quality headset.
Also, to answer one of your questions, the "surround" effect is virtual. It's all in the drivers. If the software is good, you'll be surprised by the results; I was. Before owning a 7.1 virtual headset, I didn't really believe in that. But then I bought one and it really makes a difference (in gaming, that is). When something is behind you, the sound seems to come from behind.
If you own a sound card, you MUST NOT buy a USB headset. You have to buy one with audio jacks. Also, you won't have to install the headset's drivers, because the virtual surround will come from your sound card's drivers. I'd recommend the Sennheiser PC 330
(130$), the PC 333D
(180$) or the PC 360
If you don't own a sound card, I'd go with the Sennheiser PC 163D
(160$) or the PC 333D
(180$). Both are USB headsets and feature an integrated sound card. Though not as good as a real sound card, it's better than onboard audio.