This list has changed through out the years with Empire Strikes Back always on top. After viewing the Force Awakens twice here is where I placed it.
1. Empire Strikes Back (The Masterpiece. Best film ever! )
2. Revenge of the Sith (The Machiavellian rise of the Sith Empire, the tragic fall of the Jedi, betrayal, murder, chaos, and lots of lightsaber fighting.)
3. A New Hope (The Original...Classic Knights and Cowboys in Space in a galaxy of fantasy never seen before.)
4. Return of the Jedi (Epic Conclusion. Giant Empire defeated by a small band of rebels...and ewoks...but seriously whats with the Death Star 2?)
5. The Force Awakens (An homage to the original trilogy and a well executed sequel that gives "New Hope" to the series...but seriously no more death stars.)
6. The Phantom Menace (Expands the Star Wars Universe more than any other film as we see the Jedi and the republic at the very beginning of Palpatine's accession to galactic power.)
7. Attack of the Clones (Bobba Fett is a clone? Obi-Wan is a detective? The Queen becomes a senator? Qui-Gon's old master turns out to be Sauron? Jar Jar starts the clone wars? No wonder why Anakin is messed up.)