If you have trouble with to much sun, a ND (Neutral Density) might be want you want. This gives you the option of having a higher aperture even when there is much sun.
A polarization filter might also be handy. This way you could get rid of the reflections from the ocean. Also you could get that postcard feeling with a more blue sky.
There are many people who put on a UV-filter for protection. But this is a widely debated issue. I will not go into detail about that, but here is an article on the subject. Bear in mind that a UV filter might introduce a lens flare, especially when there is much light.
You can stack several filters, like the ND and the polarization filter. However there might be problems with vignetting. This also depends upon the lens you are using.
Personally I use Hoya filters because I consider they to be of high quality. However I have no scientific evidence that they are better than other brands.