I've only been to Cozumel once, but will be going back in October. Depending on which cruise line you take, that depends on where you dock. I was on RCI, so I docked at the International Cruise Pier. On my recent and only trip to Cozumel, I went to Mr. Sancho's Beach Club. Lots of activities to do, as well as just relaxing on the beach, and there is a restaurant on the premises.
I've heard good things about Paradise Beach on Cozumel, so I may try that my next trip. Bear in mind that you are supposed to use biodegradable sunscreen, which you can get online.
2007 - Majesty of the Seas
2009 - Enchantment of the Seas
2010 - Freedom of the Seas