For an All-inclusive vacation in Mexico, you might check out
Club Viva Maya in Playa Del Carmen. They have three different restaurants at the Hotel grounds and all are included in the price. One is a buffett type that has everything from bacon and eggs, to lunch meats and cheeses. The other two are a little more upscale and I think the only restriction, is having reservations days in advance. Beers and mixed drinks are free, as well(expect draught beer and well drinks). They have activities, as well, like Kayaking in the ocean, volleyball, etc... You can also sign up for tours like going to Chichenitza(which I highly recommend)
We usually rent a house now in Isla Mujueres(an island off of Cancun), so it's been a while since we went to Club Viva Maya, but it was still a pretty good deal, if I recall.
http://mayanriviera.com/nHotels/VivaMaya/