All-inclusive Resorts, Mexico
I am really not for all-inclusive resorts in Mexico. Why? because I like my own food, and cannot stand eating restaurant food day in and day out. Having said that, it is great to just be served and spend all the time playing (and not going out in the heat for shopping).
Based on my experience, if you can stand having the restaurant food everyday, then all-inclusives are really cheap. The reason is that they get deals from airlines, so the package is not a lot more expensive than you getting a flight, renting taxies, eating out, etc. etc.
Do I recommend it? Yes, to some people.
Here is a good tutorial on all-inclusive traveling.