The Presun gel that's a favorite here seems to work the best for me, too. It doesn't make your face all greasy looking either. I put that on in the morning.

I also have been using SolBar SPF50, but wear that only when I'm out riding, as it does make your face look greasy. So far, using it on top of the previously-applied Presun is doing the job (put it on about 30 minutes before heading out). Last year, I used the Neutrogena Ultra-Sheer and didn't find it effective. I think I must have sweated it off because it made the brown patches on my face, courtesy of being on BCP, worse.