It would be a lot easier to make recommendations if you filled out your profile. Bonaire would be my first recommendation for a beginner, especially if you are close to Newark Airport. The diving is very good, as easy as diving in a swimming pool, and it's a direct flight on Continental. (Bonaire is one of the Netherlands Antilles, as is Saba. Saba has good diving, but is not a beginner's destination from what I understand--I haven't been there.)
What's your budget like? The Turneffe Island Lodge is very close to some of the best diving in Belize (and where in Belize you dive can make a big difference) and is currently running a two-for-one plus $300 for terrific accommodations on a private island. Not a five star hotel, but quite comfortable, and what it lacks in luxury it makes up for in seclusion. Only 22 guests on the island. Turneffe is also a destination for fishermen, apparently. Peter Hughes is running a "buddy weeks" promotion, where the buddy goes for 75% off. A liveaboard in Belize would offer great, fairly easy diving. The Aggressor is also discounting their Belize trips, I believe. In my opinion, the diving on the outer atolls of Belize is the best in the Caribbean.
Let us know if topside activities are a priority. That might rule Bonaire out for some people, but if your idea of topside activity is sailing, boardsailing, or visiting the donkey sanctuary, you'd be good. Little Cayman, likewise, has nothing to do but dive, but the diving is quite good.