The Caribbean is without doubt the premeire dive area in the world. Visibility is usually in excess of 100 ft and the average water temperature is 82' f. Reefs are the main attraction. Many of the islands have initiated "artificial reef" programs so now you can dive coral encrusted ships and planes.
US VIRGIN ISLANDS
BRITISH VIRGIN ISLANDS
For more information on diving the Caribbean check out the following:
Adventurers Dive Log