I'm amazed that, when I hear people talk about the best fight scene of all time, nobody mention this one. (http://www.youtube.com/watch?v=wL79E4PJ330 in case the link gets disabled somehow.)
I mean, great action, both of them are beating the bag out of each other. This is even better than Jurassic Fight Club.
For my money, there's never been a better fistfight in recorded history.