Ricardo Cantoral at 2010-09-20 19:14:28:
One of my favorite cool scenes is the "Lightning Louie" scene from Pickup on South Street. I really wish I could upload that scene to illustrate it's impact. The entire time this "Lightning Louie" character is staring straight, camera left, and eating noodles. I am not entirely sure how I can articulate how cool that scene is but it's just that. He is just so calm and collected and when he takes that money with the chop sticks, it's the icing on the cake.

Sometimes you can't explain to another person how a scene effects you. I remember watching Kinski: My Best Fiend and Werner Herzog said that the piece of acting that effected him the most was Kinski simply waking up after he fell asleep on a table.
DeafEars at 2010-09-20 22:19:48:
GOODFELLAS - the moment when Jimmy Conway realizes he's going to have to whack pretty much everybody except Henry Hill.

De Niro is the epitome of cool - and evil - here.

http://www.youtube.com/watch?v=FmF_Phk6eIE
Nate Winslow at 2010-09-21 16:10:05:
The Teahouse shootout in Hard Boiled, and more specifically, when Chow Yun Fat slides down the bannisters, gun in each hand. My 15 year old mind was blown. Still is.

http://www.youtube.com/watch?v=3wYCh5nxyCI (the bannister scene is around 2:45)

Terminator 2: When the T-1000 walks through the metal bars. So fucking cool.

http://www.youtube.com/watch?v=qnTaDjKoO2g (@2:33)

Jurassic Park: When the T-Rex gets out of his pen and first attacks the cars. Also, those special effects STILL hold up today. Which is ridiculous. It's almost 20 years old. The lead up to that, though, with the shot of the water rippling...pure Spielberg.

http://www.youtube.com/watch?v=zDegjfVi-Aw

Then...

http://www.hulu.com/watch/31365/jurassic-park-tyrannosaurus-escape

The last 30 minutes of The Police Story: nobody makes them like Jackie Chan used to. Especially Jackie Chan, these days :(.

I could keep going. I'll stop.