This is definitely a hard decision. I think blonde or blonde highlights looks more "beachy", but it may not be "you". I am trying to grow out my hair to its natural (mousy) brown just because that is what my fiance prefers (he doesn't like the maintenance and either do I), but I do love having blonde hair (it just gets expensive over time). I think you look great in both pictures, but I guess if you took out all the other factors, I would say the blonde or brown with highlights.