Coppertone
My family swears by the Coppertone line of waterproof sunscreen. I have also had very good results with Banana Boat; it is a little less runny than the Coppertone, but doesn't smell as good. I don't think it really matters since most of the leading brands use the same active ingredient; you should just make sure that you avoid the lotions with PABA if you are allergic. Also, unless you are outside all day in the blazing equitorial sun, buying an SPF over 15 is really a waste of money. If you can stay outside in the sun for a half hour before burning, then wearing 15 will protect you for 15 times 30 minutes, or 450 minutes (more than seven hours).