I think it would help if you can include activities you enjoy while on vacation, do you like to shop? Some are more suited for shopping while others have more water sports, etc. What age group are you in?
Hopefully we can stear you in the right direction with more to go on.
We are two 40-50 somethings. The younger of us likes all kinds of water sports and activites. The 50 something will do someof the tamer activites. Both of us like to shop, sightsee and enjoy entertainment. Neither of us are big drinkers.
I, the 50 something have been on two other cruises, The Fantasy and Disney. I enjoyed both, but wouldn't want Fantasy again.
I'd suggest trying out one of the Royal Caribbean Radiance class ships. They are just beautiful and a good size, lots of glass, to die for atrium. If you really wanted more activities, then there is the Voyager class and the new Freedom class. If you aren't going to use a lot of the facilities, then the Radiance class should do nicely, although I love both classes for different reasons.
All in all, I think you'd enjoy Royal Caribbean, kind of in between Disney and Carnival... Some Princess or Celebrity ships may also fit the bill, just so many to choose from and different destinations.
You might want to start by choosing what ports you would like to visit, versus cost and what port you might prefer to leave from. It depends partly on whether your interest is more in the activites in ports or on the ship. Let us know more specifics and I know someone here will have some info for you.