I haven't used sunscreen since I moved to Oregon. Here, the sun feels weak to me. I also haven't had a sunburn since I moved here, though a few times my shoulders or nose has got pink. In Arizona I used to wear sunscreen but gradually transitioned over to using long sleeves, long pants, and a big hat. I would put sunscreen on my lower face, nose, ears, neck, and the backs of my hands and tops of my feet. Here I still favor a hat and sleeves: the lotions always felt gross to me. The ones that didn't feel gross washed off too easy (kayaking) and didn't do any good. So that's my take on sunscreen. Not highly educated---I didn't even really dig into the site linked below I have a few types around the house and I'm afraid to look them up and see how carcinogenic they are. I know some of the chemicals used aren't great. I've heard that the zinc-containing kinds are most effective and least dangerous.
Sunscreen picker:
http://breakingnews.ewg.org/2011sunscreen/?inlist=Y&utm_source=2011sunscreenfull&utm_medium=email&utm_content=image&utm_campaign=toxics