Oh, THIS one is an easy one!
Army of Darkness, where "Good-Ash" encounters his evil twin, "Bad-Ash", who smacks him around, calling him "goodie little two-shoes"
The evil twin get's a double barrel shotgun to the nose, with the phrase:
"Good. Bad. I'm the guy with the gun."
http://www.youtube.com/watch?v=Q0Hmc7eeXjw
OK, you talked me into it:
Include any gun scene from: My Name is Nobody, They Call Me Trinity, Trinity is Still My Name.
My Name is Nobody:
"You know what they say? He could draw his gun three times before the other guy even starts reaching! Like this!" (Draws 4 times) "Well...we gotta shoot it out, I'm ready." (about 27 minutes nito the movie):
http://www.youtube.com/watch?v=Fxqc4lae7bI
They Call Me Trinity:
"Least you can do for a man who wants to die is wish him a cross with his name on it. You just give him your name...you'll get one." "They call me Trinity." "Trinity! Why, that's...the right hand of the devil!" (about 8 minutes into the movie):
http://www.youtube.com/watch?v=ersTjWmjJS0
Trinity is Still My Name:
"You like to see that again? It's hard to catch the first time." (about 41 minutes into the movie):
http://www.youtube.com/watch?v=Iuc8x7WITD4