Try the Sony HBH-300. If you go to howardforums you'll find a lot of good feedback on that headset with regards to voice quality. I find voice quality to be good but volume is a bit low.
There are also some mods like adding the jabra eargel and a shure (?) windscreen from those headsets to make the sony even better. I believe you can by the replacement eargels and windscreens at Radio Shack.
You also might want to look at the new Motorola 850.