Both of the below are WW (for language)
One of the best scenes from a pretty good movie that doesn't get as much credit as it deserves, was the Chris Walken/Dennis Hopper "Sicilians" scene from True Romance (kind of lengthy, but top quality):
<iframe width="560" height="315" src="http://www.youtube.com/embed/tqccyUpnZwA" frameborder="0" allowfullscreen></iframe>
One of the best scenes ever, with two of the most powerful actors of the past 40 years, was the restaurant scene in Heat:
<iframe width="420" height="315" src="http://www.youtube.com/embed/7oTNNjRuqbE" frameborder="0" allowfullscreen></iframe>
Finally, can't find a clip of the complete scene on YouTube, but the strip bar scene in The Last Boy Scout with Bruce Willis, Damon Wayans, and the "Warm Cup of ****" was great. I loved this movie, just for all of the fantastically memorable lines that Joe Hollenbeck had; like: "She's like 13 years old, and if you even look at her funny, I'm going to stick an umbrella up your a$$ and open it"