Casablanca (1942)
The film: Widely cited as one of the greatest movies of all time, this 1942 romantic drama set in World War II's African theater also birthed some of history's snappiest phrases. "Of all the gin joints in all the towns in all the world, she walks into mine" and "We'll always have Paris" are contenders in their own right. But one classic catchphrase from Casablanca beats them out.
The line: "Here's looking at you, kid."
The setup: Spoken by Rick (Humphrey Bogart) to Ilsa (Ingrid Bergman). Amazingly, this one was almost never spoken: the line was originally in the script as "Here's good luck to you, kid." Supposedly, Bogart changed the line after teaching Bergman how to play poker during the filming of the movie. The phrase may come from a poker hand that includes a king, queen and jack, since all three face cards appear to be "looking at you."