I second Tranquility Bay Resort for the snorkeling, we stayed there last May and loved it. They have a "Budget Travelers Room" which is smaller than the others but the price is reduced, I can't remember the rates but go to their website. This might be a place you might want to stay at for part of your trip if your budget is tight. This is a place you might want to get a night snorkel in right off the dock, which is lit up at night and attracts a lot of fish.