Here's the order I rate them in.
1. Return of the Jedi
Pros- This is the grand finale of the original Star Wars trilogy. All of your main villans, Boba Fett, Jabba the Hutt, Darth Vader, and Emperor Palpatine, are present and are dealt with accordingly. The naive farmboy Luke has been completely replaced with the more mature, confident, and (almost) completely trained Jedi Knight. We get to see Leia in her slave outfit
. Lando is now clearly one of the good guys. It has the best space battle scene and the best lightsaber duel of the original trilogy.
Cons- Ewoks vs. Storm Troopers. Need I say more?
2. Empire Strikes Back
Pros- The Hoth battle scene was great (I really like the AT-ATs and Snow Speeders). Yoda, one of the best characters, makes his debut. The best Han and Leia scenes are in this movie. Cloud City is absolutely georgous!. While the light saber duel in this movie may not be the best in the original trilogy, it is definitely the most powerful since it is the first real duel Luke faces and is forever changed (both physically and emotionaly) by the duel, by losing his hand and learning the secret that Obi Wan had been hiding from him all of his life.
Cons- It suffers from mid-trilogy syndrome, which I think keeps it from standing out alone as a great movie. Leia kisses her brother, eww! (although to be fair, no one knows this until ROTJ, but after knowing this it's kind of gross)
3. A New Hope
Pros- This film started it all. It's great as a stand-alone film while it is also an important compelling chapter in the entire story. Throughout the movie, it has that special magic that I can't even begin to describe which inspired all other things related to Star Wars, but diminished slightly with each incarnation. You simply can't completely recapture the magic of the original. The trench scene is classic.
Cons- It seems a little lacking in terms of pace, action, and excitement when compared to the other films, although this is of no fault of its own since this movie set the standard for action that each subsequent film had to exceed. The characters aren't quite as real and the dialogue seems a bit unnatural, but again this is mostly because this is the beginning of Star Wars, and it's full potential had not yet been reached. Everyone is miraculously clean and dry after coming out of the trash compactor.
4. Revenge of the Sith
Pros- No Jar Jar Binks! Good, though a little over-done, action and fighting sequences. I like the character development they did for Palpatine.
Con- Bad acting and bad dialogue are rampant in this movie. It suffers from "action overload" and you become desensitized to the action sequences very early on. General Grevious was poorly portrayed, especially in the light saber duel where all he did was spin the sabers and try to run over Obi Wan as a sort of light-lawn-mower. In ROTJ, Leia said that she could vaguely remember her real mother, but that would be impossible if Padme died giving birth to her.
5. Attack of the Clones
Pros- Not as cheezy or infantile as The Phantom Menace. I like how the separatists kind of mirror the Rebel Alliance of the original trilogy, except in this one the Separatists are the bad guys. The acting is decent, accept for Anakin.
Cons- Jar Jar Binks is in the movie just long enough to screw everything up. Anakin was a big dissapointment as a character and comes off as a whiny, selfish brat. The C-3PO scene on Geonosis (or however you spell it) is horribly rediculous and whoever came up with it should seriously have his head examined.
6. The Phantom Menace
Pros- It's Star Wars. It has great scenery and effects. It has a really good light saber duel and introduces the double bladed light saber (which is my weapon of choice in Jedi Academy).
Cons- It comes off as an infantile movie made for small children. A little boy "accidently" blows up a powerful space ship and safely returns when he was trying to stay out of trouble - somehow I find this sequence stretching the realm of possibility a little too rediculously thin. While the light saber duel was really well done, it takes place in a setting that could have no concievable purpose but for that very duel. Jar Jar Binks is the absolute worst thing to ever happen to Star Wars.