I don't know how you can choose only one movie ... This is a trilogy none of the movies could be seen without seeing he others ... so many elements would be missing. It is a complete story and a master piece IMO.
I love them all. Can get tired of watching them again and again.
All hail SW!!!
The Force is with you, Star Wars fan, but you are not a Jedi yet.
Star Wars fan, you're going to find that many of the truths we cling to depend greatly on our own point of view.