Revenge if the sith (done loads of lego mocs from that movie)
Empire strikes back (it truly goes through the might and force of what the empire stood for)
Partially attack of the clones the big battle at the end)
Has to be The Empire Strikes Back. No doubt about it
EMPIRE STRIKES BACK ! Those Imperial walkers were cool. Had a game years back trying to bring those down. Tough job!
The one where Luke Skywalker and Darth Vader are fighting. And then the awesomest line that Darth Vader ever said that changed the galaxy forever:
"LUKE. I AM YOUR FATHER."
The Empire Strikes Back is the best. Besides the 7th one though.