The kid thing is annoying - and I think kids should only go to the early movies, period, where you're expected to find a bunch of other kids.
It was sad, but a year or two ago there was a news story about a 3 year old who went to the movies with his parents and choked to death on some popcorn - what was even worse was they were bringing the kid to see Alien vs. Predator......that's wrong on so many levels.
My 2 year old went to see his first movie just a couple months ago - Wallace and Gromit vs. the Were Rabbit

He did pretty good, loved it and didn't really get scared, which was one concern, and we only were out in the lobby a couple times. But we took a seat on the isle so we wouldn't have to keep getting in peoples way. And it was a 1:30 movie.
D