All inclusive is good if you don't want to be bar hoppin all the time.
That Moon Palace place, there's like a main building with the lobby, restaurants, etc and then other buildings where the rooms are at. In the middle of the whole compound is this huge ass pool with bridges over it and swim-up bars.
So if you go to a place like that, you can spend a whole lot of time chillin at the pool, drinkin drinks, getting a tan, and eating at the restaurants. Then when you want to have some kind of adventure other than that, you can go to the rest of the city, or on some trip, or whatever. Like, we hit up the mayan ruins at Chichen Itza and Tulum.
Also for one day we went to this little ass town called Akumal which is one of the most beautiful places I ever been. It's about 60 miles south of Cancun. The main beach is a little bay that's separated from the ocean by a coral reef. You can go snorkeling or scuba diving right off the beach, there's all kindsa tropical fish and no boats to worry about. It's like, oh man, just friggin beautiful, and not an overdone tourist trap like Cancun. There's a few smaller hotels there, a coupla restaurants, some dive shops, nothing major. One of the restaurants has awesome flautas. Definitely worth making the trip for part of a day, or if you don't care about being around all the party atmosphere in Cancun you could just make the trip to Akumal.