Lorenzillo's for the best lobster we have ever had. On the water, on the lagoon side. Any bus will stop there for you.

It is every bit as expensive as eating in the U.S. at a high-end place, but the service and food was great. They also make a very unique Ceasar salad that I would also recommend.

All in all, we found Cancun is a rip-off for food -- caters 1000% to the Yankee Dollar, w/ prices to match, everywhere but the heart of downtown!