I won a Plantronics Audio 90 at the con. It's a very nice headset. Squaddies say the mic sounds better than my old one, and the speakers are good. In-line volume adjustment and mic on/off is a nice feature too.
I still use my old headset a lot though, since I usually run sound through my PC's normal speakers. I use it as just a headset mic, without using the headphone sound. The Plantronics set isn't as good for this, since its mic boom isn't as adjustable it doesn't rest over my mouth when the headset's earphones aren't over my ears.