Easily the Empire duel. Not only is it a satisfying culmination to everything that the film has built up, but manages to tell a story in a subtle way. It's not an action scene for the sake of an action scene, but there to develop characters. There are so many small touches that deeply contribute to the scene, like...
+The camera looking up at Vader as Luke enters. Vader is portrayed as a looming figure over Luke, an obstacle greater than himself. Vader is also largely in the shadows, which highlights his enigmatic nature (and oh yeah, he's evil).
+Luke quickly pulls out his saber and readies his stance while Vader slowly draws his. It shows that Luke is eager and anxious, while Vader is unafraid and steady.
+Vader lets Luke go on the offensive first. Luke deals some quick strikes, while Vader simply manages to deflect them (with one hand no less). Vader is learning about his opponent while Luke is focused on winning quickly (building upon Luke quitting his training due to his desire to face Vader).
+Even when Vader goes on the attack, it still seems like he is merely testing Luke instead of trying to kill him. This foreshadows his wish for Luke to join him. Vader also just stops to talk to him, further showing how so far ahead he is of Luke that he can just half focus on the battle and still win.
+Luke uses the environment and other tools to his advantage, showing his resourcefulness and desperation.
+Vader slowly appearing in the hallways references to earlier in the film where Luke fought a phantom Vader with his own face. The scene will soon reveal the two characters' primary connection.
+Vader stops attacking with a lightsaber and starts throwing shit around with the force. He is trying to show Luke that defeating him is impossible, yet joining him would grant Luke the same power. Vader eventually does start to use his lightsaber again, but is far more aggressive and overpowering.
+More framing with the camera looking up at Vader as Luke is defeated.
+Vader clenching his fist when talking about the "power of the dark side." Vader sees power as a violent construct, yet will grow to hold other values as more important. He eventually loses a hand, but not the same one he clinched with (though that was to further mirror the similarities between Luke and Vader in Jedi blah blah blah)
Nothing is wasted or meaningless in this fight. Show me the symbolism and story-building elements of ANY fight in the PT.