I really liked the duel between Palpatine and Windu, they seemed to be with in each other's reach the whole time, and the block and parley thing really worked. As for the greatest duelist, I'd probaly say that Obi Wan was probaly the greatest defensive duelest ever, which you do have a natural advantage if you're not extendending yourself to attack, and Anakin would seem to be the best offensive saberist, but its hard to say, maybe one day we'll see how he was supposively able to hunt down the rest of the Jedi. I would think that Windu was more balanced, but very much more offensive, where as Yoda was balanced as well, but much more defensive