For families with young children or teens I would recommend Royal Caribbean (independance of the seas) It is a brand new ship and the kids will love it! The ship has got somethig for everyone from rockclimbing to ice skating, water park (h20 zone) it also has the worlds first onboard surf park. for kids from 18 - 36 months check out the Aqua tots. The 6 Aqua Tots sessions encourage toddlers to explore their expandind world, through creative play, to develop imagination and to build their self confidence. Also try P+o's brand new ship the Ventura, which is also aimed at families. Although P+O do tend to be a bit more formal I would have a look at these and see what you would prefer.

We went on a Disney Cruise with our 3 children, ages 9, 5, and 2 and we had the best vacation ever. Of course, if you are not into Disney, then it would not be worth your time or money, but I would at least check out their website disneycruise.com and see if it interests you! I will say this though- we have been on several different cruises with various cruiselines and Disney had the cleanest, nicest ship we've ever been on. The room was bigger than any previous ones, the staff went above and beyond to accomodate us, and the ship has an atmosphere that is very nice and family friendly- no drunk people staggering all over the place like we saw on some other ships!