I've been to many countries as well. My advice is if you have never been outside of the United States before, it might be hard to think about what to plan/do while you are there. My girlfriends parents paid for a cruise from Louisiana, to Jamaica, to the Cayman islands, to Cozumel Mexico, and back home. I just want to say that it is actually very nice to be able to have a set schedule and not have to WORRY about what to do. Everything is in pamphlets and there is sooooo much you can do!
I'm glad I went on a cruise for the first time leaving the states (without my family, which is who I went to other countries with), so that I have an idea of what it may be like, so it's better and easier to plan the next vacation that isn't a cruise!
If you go to the Caribbean, all I have to say is find a Margarittaville to go to! They are a BLAST and have great food! Out of all the places I've been to, the ones I really want to go back to are Sydney, Australia; Cozumel, Mexico; or Hawaii! Do look into cruises though, as they are super fun and are very relaxing on sailing days! (and man do the fruity drinks just taste so good, but get you hammered xD).
But if you have the help to plan your all inclusive vacation a head of time, then good on ya! They are very fun as long as you go to the right places!