I think either Carnival or Royal Caribbean would best fit your needs for your next cruise. You'd need to decide on an itinary that you want and then pick a ship.
Some of the larger "Voyager" or "Freedom" class ships that Royal Caribbean has, have even more activities than the Carnival ships. If you want a real active type cruise, I'd try out a Freedom class, with the flow rider on the back. You'd also have rock climbing, ice skating, inline skating, etc.
If you preffer an even less active cruise, you may enjoy Princess or Celebrity as well, both have good food and decent entertainment. Since being on Freedom of the Seas, I've yet to see better entertainment, the shows after dinner were amazing, plus they have an ice show thats worth seeing too.