Consider these:
http://www.turtlebeach.com/products/pc-gaming-headsets/ear-force-z6a.aspx
They are an updated version of the HPA2 which I have and they work very well. A nice feature is the inline amp has a master volume control as well as individual control of each channel for adjustment on-the-fly without having to get into software to make changes. Once set up I leave them pretty much alone except for the bass control. Usually it is at the lowest "volume" so as to not interfere with directional cues however there are those times when something nearby is about to explode or a tank is rolling by and I crank it up.
A bunch of people are probably going to pounce on this and tell me they are garbage. However, I have tried quite a few virtual surround systems on pc and console (such as astro mixamp, CMSS3D, sennheiser hd555 (modified), logitech g35, g930 plus many more). For the pc, the hpa2's have worked the best for me (connected to soundcard with analog).
As has been stated, no matter what solution, you'll never hear footsteps of someone creeping up behind you to knife you however.