M.:
We just went on a Carnival cruise over Thanksgiving for my brother's wedding with our little girl who was 16 months at the time. I definitely would not choose a cruise again with a little one. Some of our main drawbacks with the cruise were: the "kids club" starts with age 2; if they are still in diapers, they are not allowed in the pool; naptime (2 naps at an hour and a half each per day) and bedtime (8 pm pretty much on the dot for her) was miserable because one of us had to sit in the room while she slept; getting off and on the ship in port was horrible; and debarkation in Galveston took HOURS.
I will tell you that all the staff on the ship were amazingly nice and very helpful with the baby. There was always something that she was able to eat and food is readily available 24/7. Alot of the staff have kids that they don't get to see but once or twice a year, so they love seeing the babies.
I would also suggest that you find a blow-up style baby pool to put in the shower for your kids to bathe in. I tried to find one on advice of past cruisers but because it was off season, I couldn't find one so I just had my little one sit on the floor in the shower and kind of hosed her off with the shower head. Well, she came back from the cruise with a RAGING case of ringworm on her bottom that we are still battling.
Anyway, all that aside, we did have a pretty good time, it was just really hard with our little girl.
If you do decide to go or have more questions and want to chat more, feel free to contact me. I have a very extensive list for what you need to take with you on the cruise that a more seasoned cruiser prepared.
M.