We went to South Friar's Bay in St. Kitts last February and it was great. The snorkeling was great and there weren't many people there. There are little bars up and down the beach. We just asked the taxi driver what he would recommend. I think it cost us $4 each one way to get there and he even took us to a road side bar to get beer and that wasn't on our way to the beach.
Here is a link that might help: