Being on this topic, I also recall at least two instances where actors have actually died in the process of making a movie; in both cases, the movie was rather celebrated. Heath Ledger, a very fine actor, if not one of the best, died whilst playing the role of the Joker in Dark Knight. The day after I heard about it, girls were crying over him at school. Some took the day off to mourn. Another less-recent occurrence was that of Brandon Lee's death during the shooting...er, filming, of The Crow. While a scene involving gunplay was being filmed, blank bullets were being used to create a more realistic scene. Sadly for Brandon, the gun was turned on him for the scene, and he was killed when a blank got stuck in the barrel. The next time the gun was fired, he was hit with two blanks, the jammed one having been forced out by the next shot. He was killed on impact, and the rest of the movie had to be completed with his recorded voice, as well as the primitive CGI technology of the early '90s. Needless to say, it was a beautiful film, and a very tragic loss.
Another thought: both of these movie deaths occurred while filming movies based on comics and/or graphic novels. Strange...
We need a light-hearted list after a rather heavy-hearted topic.
1. Spock and Kirk [and a tribble!]

2. Darth Vader

3. Team Rocket

4. Wizard of Oz

5. Sweeney Todd

6. Raiden [Mortal Kombat]

7. Nightcrawler

8. Dancing Panda!

9. Penelo {IRL!}

10. The Joker

11. Harry Potter Cast!

12. The Crow [technically not a chibi, but still awesome]

13. Catwoman

Aww... Don't you feel better now?
~Sushi