I would check out the Palace Resorts.
I think there's about 5 of them in Cancun... they are all inclusive.. and you can travel between all of them and eat at the restaurants, swim at pools and beaches.
We stayed at the Moon Palace. It was honestly beautiful. The beach wasn't the best but the rest of the hotel made up for it. Beautiful buildings, large rooms with hot tubs IN them, balconies with hammocks, the biggest showers I've ever seen, great food all day long, golf, tennis, basketball, etc. And a spa! They also have trips you can go on, which are included in the price. We did a snorkeling trip, a pirate cruise and swimming with dolphins at Wet N' Wild. It was a great trip! I can't recommend it enough!!
http://www.palaceresorts.com/Resorts/MoonPalace/Index.asp