I've heard that once the SPF of a sunscreen goes above 30, it no longer makes any difference. Just to be cautious though, I use the Neutrogena 70 spray of stuff which works well for me. Unless you burn easily though, you might not need an SPF that high. If you're darker then you probably won't need an SPF that high, but make sure it's high enough to protect your skin from burning. Choose yours based on past experience, it's different for everyone. I would get some sort of spray- on.
Plus if you're allergic, neutrogena is for people with sensitive skin.
Hope this helps