Now this is a good example of a thread that should be dug up once in a while.
One great thing to not say on your first date comes from an old Garfield comic.
GARFIELD: "What's your name?"
ARLENE: "They call me Arlene."
GARFIELD: "What do they call that space between your front teeth?"
ARLENE: "This relationship is off to a tenuous start."