There are always people blaming video games for the problems of society. Our 9 year old plays violent playstation games occasionally...but he doesn't go out stealing cars and beating up passers by, because he's very aware that it's all make believe.
It's the same with movies...from the time he was 2 he could look at a movie and tell you what other movies he had seen the actors in. Our 5 year olds favourite movie when she was 2 was Sleepy Hollow, our nearly 3year olds favourite last year was Resident Evil. It's how you present the thing to the child as much as anything else. If a film or video game is going to influence your behaviour, then you already have problems and you're just waiting to be set off.
There was a specific case of a young girl here in Australia in the last couple of years (I believe she was about 10-11 or so) who went to a friends slumber party, where they watched Scream on video. She had a psychotic episode on the way home, and her parents and others spent quite a bit of media time movie violence bashing. Tell me that wasn't a child with pre-existing problems waiting for a trigger.