I'm a prepaid T-Mobile user who might make three calls in a month and receive
two.  I think I've received three calls in my life while driving, and
I personally am bothered by phone use on the road.

Next month it will be illegal in California to use a hand-held phone while
driving.

What's a reasonable option for the infrequent phone user?  If it matters, I
use a V3 Razr and my car happens to have a jack on the dashboard for
connecting stuff like iPods to the audio system.  

It seems a Bluetooth earset might be an obvious answer, but strikes me as
overkill given the rare expected usage.

And while "just don't answer the phone and call back later" is a valid answer,
it turns out that those rare calls while driving have, in practice, been such
that I was glad to receive them at the time.

Informed opinions solicited.

Art