So without further ado, here's my Top Ten Favorite Movie Sword Fights list - starting at #9, since there's a tie for first place.
WARNING: Here be spoilers! Read further at your own risk!
And tying for first place...
Cary Elwes vs. Mandy Patankin, The Princess Bride (1987)
There are a couple of key differences between the setups of the two fights, though, that have an impact on the duels themselves. The duel in The Princess Bride has a playful quality to it, and while each swordsman is clearly out to win, they're not out for blood. They like and respect each other, and they enjoy taking on someone who can give them a good fight. In The Mark of Zorro, however, Power and Rathbone's characters are really trying to kill each other, giving the duel a stronger intensity. There's no respect, no "worthy opponent" mindset - they see each other as nuisances that need to be removed, and they fight like it.
By that same token, however, the Power/Rathbone rivalry doesn't really go beyond the nuisance thing. When they finally draw swords on each other, there's no real buildup to it, no long-standing enmity driving the fight, like there was in The Adventures of Robin Hood - it just sort of happens. The Princess Bride fight has a much better buildup and a more natural setup.
None of these make either fight "better" than the other - just distinct.
Adrian Paul vs. Anthony de Longis, Highlander: The Series (1992-1998): "Duende"