We went to St. Kitts in 1/08 (and bought) and are returning this March...absolutely loved the place. It is what Aruba was 30 years ago and is now gearing up as the next hot spot. A new cruise terminal has just been completed. Great restaurants and golf course; the Marriot is a combination hotel and timeshare (which is about 50% completed)...a new huge high end residential/golf course complex is being developed on the other end of the island.

For the Northeast it is probably easier to get to than St. THomas...AA has direct flights from JFK.

To learn more about St Kitts this site has a lot of info:
http://myislands.myeyez.net/index.shtml?17