Each of the original films has what could be called an 'it' moment, where the music reaches awe-inspiring brilliance and completely carries the scene in a very memorable way. Star Wars has Luke watching the sunset, Empire has Yoda lifting the X-wing from the swamp, and Jedi has Luke defeating Vader. Though all three movies are filled with excellent and wondrous scenes, these especially stand out for sheer magnificence.
(Raiders of the Lost Ark arguably has a similar kind of moment when Indy uses the staff to find the location of the Well of Souls.)