File this one under Frequently Misquoted Movie Quotes, alongside "We don't need no steenkin' badges!" which was never actually in The Treasure of the Sierra Madre (the correct quote being: "Badges? We ain't got no badges! We don't need no badges! I don't have to show you any steenkin' badges!", for those curious. Also, the quote does actually appear in Mel Brooks' Blazing Saddles, a parody of the lines in TTotSM) Getting back to Luke and his father, the correct exchange, according to the annotated Star Wars screenplays is:

Luke: He told me enough! He told me you killed him!
Vader: No. I am your father.
Luke: No. No. That's not true! That's impossible!

And thus, history was made...and then remembered incorrectly. How typical.