I went to my dermatologist (in 2005 voted #1 dermatologist in the country by other physicians) in Atlanta last week because there was a spot on my nose that I was worried about. Thankfully it was just a pre-cancer (actinic keratosis). He zapped it; now I have an ugly nose for the Fourth. He said that the only sunscreen he recommends is Blue Lizard which used to only be available at doctors' offices, but now can be bought at CVS. He says that if you put it on first thing in the AM, you're good all day (unless you shower with soap). He says that the sprays are worthless used alone because you can't get as good of a coverage with them; it's okay to use them after Blue Lizard if you truly are out in the sun all day and need a touchup.
Gosh, the sprays are so convenient, and you don't have to "grease up" when using them (I hate that feeling). But I don't want skin cancer, so I guess I'll buy some Blue Lizard before my next trip to the beach.