Sometimes their is scene in a movie that is so well made that even surpasses the quality of entire movie.
An example recently mention was:
Pirates of the Caribbean 3: At World's End
Where the Endeavor gets completely shredded by cannonballs with Beckett slowly walking down the steps.
Another one i think about is,
Sunshine, when they are racing against the sun.
Incredibles, where their plane is attacked. I believe their was a lot of rewrites to make this scene, even removing the original pilot.
The iron giant, Superman
Sometimes it's the score from a scene that enhances it, like in
The good , the bad and the ugly
Maybe it was just an actor and s(he) made the scene amazing. The fifth Element, Chris Tucker, playing Rudy
Its got to be scenes and better if they are not as well known. Pacific Rim, where the smow if falling and the little girl was running was amazing on imax.
V for vendetta doesn't count because every scene in the entire movie is good.