i'd have to say the movie that actually made me get up & walk out was "House of the Dead" that movie is so bad that the director should have been thrown into a pit of his own lame zombies. 'nuff said.
I can't say I ever walked out on a movie but the closest I ever came was during the movie Rumor Has It.... I almost did, but I figured I may as well watch the rest of the train wreck.
Dangit, I love her in movies. Another actor that will probably never overcome her television character is Debra Messing. Man, I think she should be a huge star. Shows you what I know. :/
I don't think I ever walked out of a movie. I see so few I normally have the films I go to fairly well vetted. Now there are tons of DVDs that get turned off and mailed back without finishing. Going through my recent rental activity list, here are some of the movies I attempted to watch but popped out and sent back due to lack of them catching my interest.
Leatherheads
American Gangster
Resident Evil
Witless Protection
Crank