Tough call, but the Virgin Islands sound very appealing! You could get what you get there also here in Costa Rica, but it requires some proper tour planning. Airfare is probably cheaper to the USVI than to Costa Rica.
If you decide to come to Costa Rica, just ask people here for good advice on what to do, where to stay, and where to go.
Either way, best of luck to you! May you enjoy your vacation!
Tico