We were at the live Nemo production at Disney - beautiful, broadway level production, the lights go down, bubbles come out, then, you hear my then 3 year old DS, where's the mommy, where did the mommy go!!!! He was inconsolable, it was awful.
He would get extremely stressed down during movies - like monsters inc - toy story, could do pbs cartoons. But he never got troubled by all the books that started with dead parents, but did have trouble when parent or cared about person dies in middle. He explained it to me at 5 as that in books he can skip ahead, what he really couldn't tolerate was the pacing of movies and that he had no way of knowing all would work out. Now at almost 8 he watched the Incredibles and had no trouble with the torture scene but flipped out at the end of the phineas and ferb movie where perry is watching the pictures of his family he is not supposed to have. Oh and we just saw his first in the theater movie - despicable me 2 this summer.
We went with the theory that his childhood would not be stunted if he didn't see the movies, and he was never asking to see them either. We read the Star Wars books first because he wanted to see those movies and doing that helped. There is really no harm in waiting and I think it does get more tolerable for them. At least it did for mine.
DeHe