Vader vs Luke in empire. I like how Vader could easily have won, but he played with Luke instead.

Empire's Luke and Vader fight felt powerful to me. I honestly liked the largely realistic movements and struggles conveyed by the older movies. Normally I'm not a junkie for that kind of stuff, but seeing Luke struggle as much as he did just to keep up and manage to overcome Vader here and there (even if Vader was going easy on him) felt wowing.

I know they don't exist in the same world but I love to see a huge battle between the two Sith Powerhouses.
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Revan Vs Star Killer

This is just the another voice saying Obi vs anakin because of how intense and emotional it was. Like these are to gaits who are brothers, father and son, etc and they are trying to kill each other because anakin was lost to the dark side and Obi-wan couldn't allow the sith win. It was by far the most epic and saddening duel of the entire Saga

if its a lightsaber battle it is Anakin vs obi-wan but if its any sorta battle its gotta be battle of geonosis