A lot of people just spoke out against USB mics, and Chalenge (naturally) suggested a very expensive mic. So I want to relate a counter example, since my experience with my USB mic has been flawless.
I just checked my Newegg history and I bought
this mic on July 18th 2006 from Newegg for $18.99, and the exact same item is still available from Newegg for $1 more, and I'm sure you can find it elsewhere, including retail stores, if you want.
http://www.newegg.com/Product/Product.aspx?Item=N82E16836111601That's nearly 5 years, and its been flawless that entire time. The only time I've had any trouble was when I was an idiot and plugged in the USB cable loosely, or I didn't have the game or Windows configured to use the mic instead of the mic jack on my sound card.
Its not a headset mic though. If you don't want or can't use a desktop mic, don't buy this. Otherwise I highly recommend it. Its not going to fail on you in less than a year if your experience is remotely similar to mine, as I've had mine for 4.5 years now, and its showing no signs of being anything other than just as good as the day I took it out of the box.