I have one, but only use it when someone else is using one. I never want to be "that guy". It's rare, but on the occasions i do, it leads to some great moments.
For example, playing RDR, I went into a game of Liar's Dice, and 3 other guys were using mics, so I joined in, we joked around and decided to hang out in Free Roam. We friended each other. It turns out one of them got Dead Rising 2, so we both helped each other in co-op (and let me just say, mics are a MUST for playing DR2 online.) Now we all have Black Ops, and some serious lulz happen.
For example, playing RDR, I went into a game of Liar's Dice, and 3 other guys were using mics, so I joined in, we joked around and decided to hang out in Free Roam. We friended each other. It turns out one of them got Dead Rising 2, so we both helped each other in co-op (and let me just say, mics are a MUST for playing DR2 online.) Now we all have Black Ops, and some serious lulz happen.