Where to see yachts in the Caribbean

I'm going on a cruise to the Caribbean in a few weeks (March 24) so I wanted to ask around where the good places to see and take photos of megayachts are. The islands I will be visiting are: Puerto Rico, Barbados, St. Lucia, Antigua, St. Maarten, and St. Thomas. What marinas are there? If I get some good pictures I will certainly post them when I get back.