I know this is a late reply, but I have just joined.

One of the best dive spots in the Caribbean are the Islands of Saba and St Eustasious. Saba was voted best caribbean island in 2006. It offers great deeps dives and has the only decompression chamber in the north eastern caribbean. Statia which used to be the largest trading port of the caribbean has the old foundation sof its old city sunken under water.
I have never dived these locations but having worked for the airline that services these two destinations I have taken many experienced divers across. These islands are off the between path, most people have never heard of them I would definately recommend researching them.
Best way to get there is to fly to St maarten through any major US airline or Air France KLM. And then take Winair which has codeshare agreements with a bunch of airlines as well.
Hope this helped.