I nearly get irate every time I see people driving with a phone held up to their ear. One day the first 13 cars I saw had morons driving while on the phone.
I've been using a Motorola H3 for over a year, and I love it. Auto-answer, one touch name recognition or voice dialing rocks. I leave it in the car and put it on every time I get in. Yeah, I do wear it into the store if I'm expecting an important call, but do think its rather ghey to wear it outside the car otherwise.
These things are CHEAP! I don't know why everyone doesn't have one. Please, for the safety of all of the rest of us, yeah that's you the 4 foot tall soccer mom in the sport-utili-bus filled with 3 kids and a dog, GET A FUCKING HEADSET!