My hat is tipped to the private islands in the Bahamas which are owned by Carnival and Royal Carribean. My gosh they are some beautiful places. Also, I loved Belize! I have never ever seen clearer water. I snorkled off the coast at a place called 10 Tree Island. Amazing! If you don't mind being jerked around by the locals, Jamaica has some beautiful places in Ocho Rios. Dunn's River falls were a blast.
Although it got bad press about a year or two ago, I would reccomend Aruba as a top notch place for all kinds of fun. If you have never been, then I highly suggest it. If you have the money and time, spending extended days there is a must in order to take it all in...so much to see. It has all the qualitites of other places in the Carribean, and much more. Hope this helps.