I have Steelseries 4xB's and they are pretty good for both.
Nobody has complained for ant bg sounds (on Xbox), but on PC I have to crack up the Mic volume.
One downside is that the cable is really short (about 0,5m), so when I use it on the PC it doesn't give me much room to move.
If the Turtle Beaches came with some sort of adaptor for the 360, I would suggest that you buy the PC version Steelseries. I hear that Siberia V2's are pretty good, and they cost only about 70€ ( don't know how much in dollars)
I hear that's the site you get everything around your side of the pond