Ranked in the order of which movies I watch and/or think about the most:
1.) The Empire Strikes Back -This seems to be the consensus favorite. Nearly flawless from start to finish. Didn't like some of the 1997 & 2004 alterations except for the addition of Ian McDiarmid as the Emperor in 2004 but then they went and changed the dialogue which kind of irked me. Nonetheless, still the best!
2.) Return of The Jedi- This has always been my second favorite movie. Yeah, Wookies would've been cooler than Ewoks but the Ewoks didn't bother me as much as they seem to have bothered most people here. There's also plenty of good stuff happening in the movie that FAR outweighs the battle on Endor with the Ewoks.
3.) Revenge of the Sith- The BEST of the Prequels and nearly on par with my first two favorites. Save for a couple of minor things, the movie was awesome from start to finish. The scene with the Clones turning on the Jedi (Order 66) was simply heartbreaking to watch. Also, the scene where Anakin has to decide whether or not to save Palpatine is a neat parallel to the scene in ROTJ where he has to make a similar decision about whether or not to save Luke.
4.) A New Hope- I don't watch this one too much anymore but it IS the original movie and a nice straightfoward "popcorn movie". I l really like the NPR Radio Drama adaptation of it as it REALLY fleshes the characters and some of their backstory out.
5.) Attack of the Clones- A good prequel that ultimately falls a bit with me short due to some of the romantic scenes that pretty much monopolize the middle act. The first and last acts of the movie, however, were really quite good and I ended up being quite pleasantly surprised by the introduction of Christopher Lee as Count Dooku, as well as the twin revelations that the Clones fight WITH the Jedi during the Clone Wars and that the Republic eventually becomes the Empire (as cleverly foreshadowed by John William's use of the "Imperial March" cue in his score for the movie).
6.) The Phantom Menace- I thought that TPM was a pretty good movie but I didn't quite understand the significance of the people, places, and things they introduced in the movie until later in the PT. I loved Liam Neeson's Qui-Gon but was sad to see him killed off so soon in the PT. It would've been interesting to see him have some kind of interaction with Dooku in AOTC. Plus the whole "virgin" birth thing with Anakin? WTF????

It would've been better if they had just left it with Shmi just not wanting to reveal the father or something else. Also, I don't really care about Midi-Chlorians as I felt that that kind of "de-mystified" The Force. Also, an ELECTED Queen at age 14???

Children sure do grow up fast in the SW universe. Anybody else ever notice that?
Edit: I didn't think about including the Clone Wars "movie" in this list because, although it was released into the theaters, it really seemed more like a TV series (as it was originally intended to be shown). Still, it was a pretty good introduction to the TV series and I liked how they got Christopher Lee to reprise his "role" as Count Dooku (I believe that Samuel L. Jackson contributed his voice to the movie as well but he was barely featured in it). It was also just nice to have Star Wars back on the big screen when I never expected to see any new Star Wars material on the big screen.