The whole intro to Patton
my two favorite:
"Now I want you to remember that no bastard ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country."
"Thirty years from now, when you're sitting around your fireside with your grandson on your knee and he asks you, "What did you do in the great World War II," you won't have to say, 'Well... I shoveled s*** in Louisiana.' "