Mr. Sandman at the end of Halloween II... had a certain pleasantness and creepiness to it at the same time. Here, a mass murderer is subjected to an explosion, is walking out completely on fire, and falls flat on his face, completely engulfed. Cue Mr. Sandman.
Of all the movies listed above, I wouldn't have been able to think of the ending music for the vast vast majority of them. But, Mr Sandman really sunk in 30-some years ago.
edit: oh, another one I just watched again the other day,
Always Look on the Bright Side of Life - ending credits during Monty Python's Life of Brian while they're all being crucified. I always find myself whistling to it.
http://www.youtube.com/watch?v=WlBiLNN1NhQ