I think most of us agree that using a cell phone while driving is distracting.
I've also found myself distracted and/or driving unsafely by these things:
Kids arguing and/or acting up
DH not liking the way I drive
Not being able to read the street signs (or even finding them in some intersections)
Garage sale signs with miniscule writing and arrows on them
Eating while driving
Looking for something while driving