Rebecca is collecting everyone's favorite Princess Bride quotes. My favorite is probably "Hello, my name is Inigo Montoya. You killed my father: prepare to die." It is already listed; but a close second would be this exchange:
Miracle Max: He probably owes you money huh? I'll ask him.
Inigo Montoya: He's dead. He can't talk.
Miracle Max: Whoo-hoo-hoo, look who knows so much. It just so happens that your friend here is only MOSTLY dead. There's a big difference between mostly dead and all dead. Mostly dead is slightly alive. With all dead, well, with all dead there's usually only one thing you can do.
Inigo Montoya: What's that?
Miracle Max: Go through his clothes and look for loose change.
I mostly just use "There's a big difference between mostly dead and all dead. Mostly dead is slightly alive." And a third would be this exchange:
Vizzini: He didn't fall? Inconceivable!
Inigo Montoya: You keep using that word. I do not think it means what you think it means.