Here's one, I don't know if it's already been said:
"Uh, yeah. I WOULD declare war, but my advisors seem to have lost the paperwork" - Cleopatra
"Confound you! We'll march to your cities with my armies...er, as soon as we'll get around to it" -Lincoln
"You are fortunante that your pathetic civ isn't even worth destroying!" -Xeres
"Just checking your border security, Hammurabi. And to tell you the truth, it's not too good." - Xeres This was when I just established a city and there was no defenders.
"Like your skull, your threats are empty." -Mao
"Japan is a paper tiger. Your threats are refused" -Mao
"With friends like you, who needs enemies? We decline" -Lincoln, gracious
"Well, it's cutting me own throat, but we can accept this" - everybody
"See? THIS is what happens when you judge leaders by their social standing. It wont' happen again!" Elizabeth.