My wife and I sailed on Carnival Ecstasy, leaving Galveston March 10, 2007, stopping in Cozumel and Progresso. As a point of reference, my wife won the cruise as a radio station prize, so there's certainly a bias towards enjoying the cruise, since the basic part of it was free! However, we'll try to be objective about it, and have some pointers that might be helpful to other cruisers. We're in our early 50's, no children.
First of all, we did get an enormous amount of useful information from reading the CruiseCritics reviews of the ship as research, prior to our going on the cruise. Thanks to all (both the positive and negative reviews), and I hope our review can also be helpful.
We packed 3 suitcases (all rolling), and a rolling cooler that we got from Sam's Club for $24.99 - invaluable! Also a backpack for important items such as documents, medications, etc. In retrospect, we should have brought 2 backpacks to use on the shore excursions - it would have distributed the weight much better, particularly when you're carrying multiple bottles of water. In the heat of Cozumel and Progresso, take as much water as you can carry, because it's very easy to get dehydrated.