I have the Turtle Beach DPX21's. I think I bought them shortly after I started playing Black Ops, I had played MW2 but didn't use a headset for the game, I just tended to mute everyone. Now I only mute people that play music, are overly loud/offensive, etc.
I really like the headset. The sound quality is good, and it definitely made a difference with being able to locate/hear enemy players so much easier, especially when I've had Ninja Pro unlocked. One of the key features, which a lot of headsets share, is the ability to control Game volume and Chat volume separately with sliders.
The other reason why I'd recommend Turtle Beach is the one year warranty and generally good customer service. I have a friend (really, this isn't me!) who had a problem with the swivel joint by one of the ear cups breaking, and mailed them to TB, they repaired or replaced his headset. Even if you have to pay for shipping (I didn't ask) that beats paying another $50-150 for a new headset. Most of us don't have a money tree in our backyard.
[Edit: I know you asked about wireless, but corded ones aren't that bad.. the cords are long and you don't have to worry about charging or batteries decaying over time since they're powered via USB.]