i dont like the 360 headset either, but its the stock one. Nothing much you can do about it, and is perfect for casual gaming. no need to go out of your way for a better one, but it
Turtle beaches are nice ones that run between 50-60, which offer surround sound.
I have 240$ astro headsets which is insanely overpriced, but is the best one out on the market. That was back when i was into competitive gaming, but the sound quality is superb, and offers for a lot of things to be done, including using it as a pc, ps3 mic, listening to music, turning the volume up and down for separate things, and so on.
But then again, youre just playing left 4 dead, so i would just keep the ones you own.