I adore Return of the Jedi. It has such a great, uplifting ending despite the hardships all the characters went through. The conflict between Luke, Palpatine, and Vader is so darned great, too. Great dialogue, great, lighting, great music. <3 I think after that, A New Hope and Empire are probably tied for second.
I have to shamefully admit that I have a soft spot for The Phantom Menace because it was the only one I saw in the theaters and, I dunno, there's something weird and interesting going on in that movie that holds my interest haha.
I might have to put The Force Awakens at the very bottom just because the movie is so derivative. Not the biggest fan of The Last Jedi, but at least they tried to take the material in a different direction in that movie (sort of). Attack of the Clones is pretty hard to watch, too. XD