'Casablanca' (Best Picture, 1943)
Hollywood as we know it wouldn't be Hollywood as we know it without a handful of foundational films. Casablanca is one of them, and unlike several others (Citizen Kane and The Wizard of Oz come to mind, though Oz lost to the equally influential Gone With the Wind), it won the big prize. As integral to our culture's conception of romance as Romeo & Juliet, it pulls off the neat trick of being simultaneously cynical about love's long-term prospects and passionate about giving it a shot anyway. And, of course, it's endlessly (mis)quotable.