I will say one thing about all-inclusives... depending on what specials are available, sometimes you can save money even if the only things you will use the AI part for are drinks at poolside and breakfast. Personally, I am NOT a morning person, so I prefer to have breakfast at my own hotel, not getting up extra early to go out somewhere. I just went to Cozumel last week, and it was only about $15 a day more for the AI deal, compared with the other hotel we'd been looking at. Considering $4 a day for breakfast, 2-3 drinks while relaxing by the pool, a couple drinks while waiting for my friends to meet to go to dinner, and possibly a midday snack... it totally made up for it. Also, I was RAVENOUS after my first day diving, and we all dropped our equipment and attacked the buffet, still covered in saltwater, with wet clothes and all.
So, it can be worthwhile depending on the deal. All that being said, I do try to go out to as many different restaurants as possible when I go to Coz, because there are so many good ones! So, even if you go AI for the convenience, DO NOT eat every meal on the hotel property, or you will serisouly be missing out!