What defines a great scene? That's another one of those personal things. I'm trying to think of a great scene that's appropriate, cause I'm into all those really warped movies...
Well, here's a scene from my favourite movie of all time, 'The Wall', that I think is great, my favourite scene I probably shouldn't post because it has some fairly graphic subliminal sexuality, but this scene still showcases the films wonderful animation, powerful music, and intense use of metaphors.:
http://youtube.com/watch?v=iXgxemYiXQ4
This scene is from the 1950's classic 'Sunset Boulevard' when the reporters come to Norma's house to report on the murder she committed, but in her insane fervor she thinks that they are there to shoot her dream, her final picture.
[ame]http://uk.youtube.com/watch?v=VhlhE32SoXs&NR=1[/ame]
This next scene is from Charlie Chaplins first talking film, the extremely funny and extremely powerful film 'The Great Dictator.' It was an obvious statement and mockery of hitler, and this scene is not meant to be a comedy scene, but it is where the 'Jewish Barber' character is mistaken for Hinkle (The 'hitler' character of the movie) and has to give a rally speech, and of course, as he is not the monster that Hinkle is, gives a much different speech. It's a very powerful scene, in my opinion, and makes a very good statement on the world:
http://youtube.com/watch?v=QcvjoWOwnn4
And another great scene from 'The Great Dictator' that just shows off Charie Chaplins excellent talent is the classic globe scene, it's a metaphor but even if you don't catch the metaphor, it's still a well choreographed scene

This is when Hinkle ponders his conquering of the globe.
http://youtube.com/watch?v=IJOuoyoMhj8&feature=related