[Rain Man]

My votes in a diverse set of scenes:

#1 - Back to the Future. This may be the quintessential scene from a great movie. I like the little shriek at around 0:32. Christopher Lloyd is entertaining.

#2 - The Alamo. Did Davy Crockett play the violin? Eh, I liked the music.

#3 - Super Troopers. It started out pretty entertaining, but I think it was two scenes. And it went downhill as it progressed. If it cut off at about 3 or 4 minutes, I might rank it higher.