Hard to choose -- for me, I think might be a three-way tie.
~ from My Man Godfrey, 1936:
"All you need to start an insane asylum is an empty room and the right kind of people."
~ Cary Grant to Katharine Hepburn in Bringing Up Baby, 1938:
"Now it isn't that I don't like you, Susan, because after all, in moments of quiet I'm strangely drawn toward you... but, well, there haven't been any quiet moments."
~ Clifford the Dreadlock Rasta Muppet dude, in Muppets From Space:
"Oooooooh -- Shenaynay!!!"