You can't go past Firefly for a good put-down:
"Do you know what the chain of command is here? It's the chain I go get and beat you with to show you who's in command!"
"Mercy is the mark of a great man." (stabs helpless opponent.) "Guess I'm just a good man." (stabs him again) "Well, I'm alright."
"This distress call wouldn't be taking place in someone's pants, would it?"
"The girl knows things. Things she shouldn't. Things she couldn't."
"Wha-? Are you- are you sayin' she's a witch?"
(pause) "Yes, Jayne. She's a witch. She has had congress with the Beast."
"She's in Congress?!"
"How did your brain even learn human speech? I'm just so curious."
Captain: "Zoe, the ship is yours. Remember: if anything happens to me, if you don't hear from me within the hour, you take the ship -- and you come and you rescue me."
Zoe: "What? Risk my ship?"
"Do you really believe that?"
"I do."
"You willing to die for that belief?"
"I am." (pulls out a gun) "Course, that ain't exactly Plan A."