Also being someone who spends a great deal of time on the water I can chime in with my 2 cents. Buy the B+W!

Brass rather than aluminum. Lots of time in the sun could equal high temperatures and water spray. Aluminum will slowly oxidize, whereas brass will not. Also, the brass rings on B+W filters tend not to get stuck as easily as other filters made of aluminum, because of the difference between the filter and the lens. (2 opposing metals).

Time on the water = a lens getting splashed, it's just a given. A high quality filter will not only help protect the lens but will be easier to clean. A drop of water on a hot camera lens can be a real PIA to clean. Also, salt water spray tends to corrode the protective coatings on glass, so high quality MRC coating is important.

I like the heaviness and build quality of the B+W's as well.

I've had a 7D for just over a year now and love it....BUT knowing what I know now, I'd give up the fast frame rate and take the Full Frame of the 5D. I'm a Canon guy and would never buy a Nikon so I plead ignorance about the D7000, but if it's full frame and compatable to 7D I'd say get it.