3. Orson Welles - The Transformers: The Movie
Nothing on the list saddens me more than this. Orson Welles, who made what is often called the greatest American film ever made (Citizen Kane), ended his career performing voice-over work in what amounted to little more than a big screen, feature-length advertisement for Hasbro's line of Transformers toys. There are probably people out there that have fond memories of this movie. Plus, it featured the voice talents of Eric Idle (of Monty Python fame) and Leonard Nimoy (the original Spock). But perhaps most importantly, it still holds up better than any of the live-action Michael Bay disasters. So it's not necessarily a bad movie itself, but rather it's the stark contrast between his theatre wunderkind days to peddling kids' toys that makes this such a notable (and tragic) point in Welles' career.