Unless you've lived under a rock in the last twenty-plus years, you've heard of this movie. To me, Empire Strikes Back is the sequel to end all sequels.
Darker, richer in character development, and more psychologically complex than A New Hope, Empire moves the Star Wars saga into new territories. Director Irving Kirshner expertly juggles each aspect of the film from action, to romance, to quiet moments of introspection with Luke and Yoda on Dagobah.
Plus, who can forget the final moment in the film when Vader reveals to Luke that he is his father??! Still sends chills up my spine!