My wife and I are in the process of trying to plan ourselves a vacation for this summer. We're looking to go during early to mid July. I'd love some input on this from some tropical minded folk.

We're looking to go international, and pretty sure we're headed to the islands or Mexico/Central America. We've looked at so many books and videos that the places are starting to run together. I'd love some advice/suggestions.
We went to Aruba 2 summers ago and loved it. We are looking for something similar I suppose. We're in our late 20's. Definately want to be at a beach with the option to move inland. We'd like the ability to have a few drinks at a beach bar

, have a number of dining options, some boat excursion opportunities, etc. Somewhere with forests and waterfalls, etc. would be a plus. We don't have tons of money for this, so the more expensive places and flights could rule some out. Some sightseeing choices would be good (volcanos, rainforests, inca temples), but sleeping in a mosquito net or swimming in a hurricane are not so good. Would also prefer a hotel over a hut and a fixed destination (or two) over a cruise.
I feel like places like the Virgin Islands & Puerto Rico are going to be too much like home. I'm trying to get some mileage out of my passport before I'm dragging a stroller on vacation with us.
Anyone have any suggestions/comments?