Ranking the lightsaber duels! This is what I think and why:

1. Episode III: Anakin and Obi Wan (had everything).
2. Episode V: Luke vs Darth Vader (Vader is in control, great sets/action).
3. Episode I: Obi Wan/Qui Gon vs Darth Maul (worse movie, one of the best duels. Slips down to here because I had the least interest in the characters as a whole. This counts as the whole duel - from Darth Maul turning on his double lightsaber to Obi Wan cutting him in half).
4. Episode VI: Luke vs Darth Vader (good fight, but intensity was continuously hindered by the Emperor's interruptions followed by Luke's hesitation. Luke clearly showed his progression as a Jedi. Fight ended well with Luke's rage).
5. Episode III: Anakin/Obi Wan vs Dooku. (Great short fight that steered Anakin more towards the dark side. Clearly shows Anakin's progression as a Jedi and had a cool ending).
6. Episode V: Luke vs Darth Vader in the tree on Dagobah (cool, slow motion fight with a cool ending).
7. Episode II: Obi Wan then Anakin vs Dooku. (Should have been a lot longer. I won't even consider Dooku vs Yoda - that was just a plain stupid fight).
8. Episode I: Qui Gon vs Darth Maul mini fight on Tattooine (short artsy-####sy version of what was to come later).
9. Episode III: Windu vs Palpatine (short but good, served its purpose, finally got to see the purple lightsaber in some real action) and Yoda vs Palpatine (similar to the Episode II, but much better and less silly).
10. Episode IV: Obi Wan vs Darth Vader: The Final Battle (the one that started it all, but George Lucas summed it up best: that it was a fight between an old man and a half man/machine. They did not move well and it just did not look that great. The psychological aspect of this scene is much more significant since the release of Epi III).

I'm sure there will be differing opinions, I had intended for just the main duels to be evaluated, but might as well rank all the scenes that had any lightsaber on lightsaber contact...