Yeah, I would not go for any cockatoo if your a first time medium parrot owner. A grey prefers to like one person, but all the greys I know adapt beautifully for a large family. I would get a gray as a baby and then train it to be used to little fingers and noises. Grey's are big hits with kids because they talk a lot, but Greys overall like quieter households. (I visit the place I got Sarah from and her grey love meeting new people, but ALL birds are different)
Cockatoos not only are loud, but very messy as they like to make messes. Put are the cuddle buds. They will scream for attention no matter how much training. IF someone can usually be with the bird and your family can ignore the neccesary screaming at morning and evening. Plus, cockatoos tend to be moody, sweet and cuddly and then all of a sudden something can tick them off and they bite. I know that one bite is enough to make some kids horrified of the bird.
AS you say you never go back. The way I see it you just ought to keep a pet for three months cuz after that it is impossible to give them up, because they sweeten up eventually. Cockatoos have to be the most active parrots ever!

Plus many just walk around on the floor and chew as they please. It is near impossible to stop once it has started, and I have to admit, I just live with it...
Cockatoos are harder to take care of than dogs...trust me...
Do you have any ideas where you would put the cage? That is an important factor too. I only have personal experience with a cockatoo so, I have no idea what other birds to recommend. If you could please tell the amount of time you have to give, and places you could fit a cage.