I just got back from my cruise TODAY. I went on the Carnival Victory out of Miami and went to St Thomas, Puerto Rico, and St Martin. I went with my roomates so we didnt exactly get the family expierence. I saw alot of kids on the ship and they looked like they were having alot of fun. Cruises are really good about catering to everyone in the family. They have tons of kids stuff so your daughter wont be board. And plenty of adult entertainment so you guys will have a great time too.
Ive been on Celebrity and Princess cruise lines as well those seemed to be more family oriented. I was younger when I went on those so it just might have seemed that way.
TO DOS: Get a exterior room having the balcony is sweet. Makes everything better even though you wont be in the room much its cool just to chill and watch the ocean. GAMBLE!! I had a blast, I learned how to play craps and made a good amount of money. Go to the shows they usually are really good. If you or your wife like to shop St Thomas is a sweet place to go. They dont have sales tax and stuff is usually alot cheaper there. Go check out the islands and if you go to Puerto Rico go to Marias bar. They have a drink thats called the Los Notos or something like that and its amazing.
Donts: Dont stay in the room long! You will miss out on all of the fun there is a tun of stuff to do any time during the day. Dont get the drinks they bring around in the "cool" cups because those are expensive and barley and liquor inside them. Get your drinks from the bar watch them make it they were alot better when we did that.
I would totally recommend going you and your family will have a blast. It would be border line impossible not to have a good time on a cruise. Your daughter would have a blast because she would be able to do all the kids things. They have a full staff just dedicated to kids. You and your wife would just be able to chill and thats what vacation is all about.