Ray Bradbury has ripped into Michael Moore, calling him an "asshole" for "stealing" the title for Fahrenheit 9/11 from Bradbury's novel Fahrenheit 451. Yeesh. You'd think that someone who's worked all his life in a genre where practically everyone has written a book or story called "Nightfall" would have figured out by now that there's no copyright in title, period, end of story. God, I hate it when my literary heroes turn out to have feet of clay. This is even worse than the time that he dismissed the Internet as a scam and compared MMOs to pinball machines.
"[Moore] is a horrible human being – horrible human!"
When asked if he agrees with Moore's political positions, Bradbury replied, "That has nothing to do with it. He copied my title; that is what happened. That has nothing to do with my political opinions."
Update: Brian Dear comes up with examples of Bradbury's works that take titles from other authors, from "Something Wicked This Way Comes" to "I Sing the Body Electric" to "The Women."