Jawbone Bluetooth Headset
Lots of buzz, but I think it lives up to it.
After trying one out, we bought them for all three partners in our company.
I really like how well it eliminates background noise. It seems like my phone is always ringing when I'm in a noisy place like when the legislature is in session and I'm on the House floor. Now the people I'm talking to usually have no idea what is going on in the background.
I've also been very impressed with the talk time. I have the black one, but they are also available in gray and red.
The hardest part though, with any of these headsets is keeping track of where they are.