If you like Italian, I can recommend two restaurants. One is La Dolce Vita, on the lagoon side across from the Marriott Casa Magna (great view at sunset). Here is a link to their web page. http://www.cancunitalianrestaurant.com/

The second is Casa Rolandi, in the Plaza Caracol (excellent crepe suzettes). In six trips to Cancun, I've always dined at each of these at least twice during a week's vacation. Here is the link to their web page:
http://www.rolandi.com/crc_about.htm