Best action scene in a movie?

From Double Team
http://www.youtube.com/watch?v=TT2aSoIYMUk

Pardon the annoying and completely pointless overdubbing...

Endhiran

The Man From Nowhere (아저씨)
http://www.youtube.com/watch?v=dv5sdKqHdCw . Best knife scene ever. But i only recommend watch the full movie first for much more impressions.

Nothing beats this :P
Enthrian

This is epic Van Damme in Mortal Kombat: Bloodsport Edition

The Oldboy hallway scene comes to mind - one take, pretty impressive.

The scene from Heat.

That long take from Children of Men.

The opening of Saving Private Ryan.

And then there's this masterpiece.

This is the first thing that comes to mind.