You may find this idea a bit unorthodox: Havana. I know someone who went there a couple of years ago -- this is someone who has been all over the Caribbean, and they said Havana was one of the nicest places. Apparently it is the most visited destination in the entire Caribbean -- just not by Americans. You have to travel through Canada or Mexico to get there. But it is supposed to be extremely nice, and because of the favorable exchange rate, also inexpensive compared to many of the other vacation spots in Caribbean.

http://www.cubatravelus.com/