Yes, that one from Vaquero was the first to come to mind. Undoubtedly my favorite. xP
"I shall eat your heart and spit it out, terran" and "you're going home in a box" I liked too... especially the second just because of how the words tumble out. The taunts were almost all good though, I'm glad there was variation and specials for aces. ^^
Nomad Terror beat me to the punch. Vaquero's taunt there is my all time favorite, too, mainly because he's so laid back and easy going when you talk to him on the ship. Actually, Vaquero has got to be one of my favorite wingman to fly with in the entire WC series, along with Hunter...
A close runner:
"I don't believe we've been introduced. I'm Maestro. You're Dead!"