NotStarring.com is absolutely addictive! The actors considered, and sometimes even hired, for films before the role went to somebody else is amazing and thought provoking. Scorsese
passed on Schindler's List because he thought the film needed to have a Jewish director (a decision mirrored by Steven Spielburg when he passed on The Last Emperor--oops).
So they offered it to Roman Polansky, who turned it down because as a Holocaust survivor he was too close to the project's topic. California-born Spielburg took the gig instead (having just realized he wasn't actually Chinese). Actors considered for the lead part include Harrison Ford, Mel Gibson (!), and (wait for it) Alan Thicke. That is not a typo. You probably thought reality couldn't top Mel Gibson for this part. Really, Alan Thicke.
Now, imagine Michael Stipe as the killer in
Seven vs Denzel Washington in the Brad Pitt role. Or picture Stephen Baldwin or Jeff Bridges screaming "get off the bus!" to Ellen DeGeneres or Halle Berry in
Speed. At least the part didn't go to
Tom Cruise, the star of Donnie Brasco, Cry-Baby, Edward Scissorhands, and (wait for it) Footloose.