I'll be the first to say I've been guilty of this at one time or another. But when I'm texting, I'm at a complete stop... or if I'm on the go (Vlingo FTW!).
The one person that scares the living dookie out of me is my wife. I'm constantly on her case about her texting while driving.. especially when our 3yr. old son is riding with her.
I just hope one of these days she wises up, and doesn't have to find out the hard way.
It's bad enough that you're behind the wheel of a 2,000+ lbs. killing machine that could cut through a crowd of people (and some buildings) like a wedge.
By all means people, just don't do it while driving.