the biggest mistake a lot of gamers make is buying into the whole "gaming headset" gimmick, and basically that's all it is, a gimmick, they overcharge for a set of headphones with a usually crappy mic, the build quality is actually pretty poor and the headphones aren't good for anything but gaming because of the sound quality, get a good set of cans and a clip on mic and you'll really notice the difference in the sound quality...
I started with the RAZER Barracuda HP-1s and thought they were the greatest thing since sliced bread, EAX, built in mic, OMFGBLUELEDS!!1!1!1!, etc., then I tried my JVC HA RX900s after reading up on the internet about what headset/phones were the best for gaming but didn't cost and arm and leg and these fit the bill perfectly for gaming AND music, they aren't the best out there like Audio Technicas, or high end Sennheisers, but they have comparable sound for much less, these are basically the bang for buck king of headphones...
JVC HA RX900
yes they're big, but they are supposed to be to cancel out all outside sounds so you can concentrate on the directional positioning of sound in the game, a crucial but underrated element in FPS games, one guy even accused me of running a wall hack because he thought I could "see" him behind a wall, when I really just heard him shuffling around on the gravel inside the barn...
RX700s are actually better for music and even cost less, but the 900s have a bigger soundstage which helps with larger maps in games, add a Zalman clip on mic and you're good to go for less than the cost of most "gaming" headsets, the JVC 700/900s have been called the "poor man's Audio Technica 700/900" because they cost so much less, just my .02, but if you do some research you'll see that I'm hardly alone...
one thing though is that with any good headphones they sound pretty bad out of the box and need some "burn in" time, mine took a few weeks to burn in, but once they did and I put the Barracudas back on for a session it seemed like there was a layer of water between the headset and my ears, that's how muffled the Barracudas sounded and how much clearer the 900s sounded...
