I love this gallery at Life.com that shows just-missed film roles. I think it's fun to imagine movies as they might have been if casting had veered off on a slightly different course. Shirley Temple as Dorothy Gale? Laurence Olivier as Vito Corleone? O.J. Simpson as the Terminator? (Check out the gallery... James Cameron makes the joke that you're thinking right now.) Film history could be so different.