For western fencing, the preiously mentioned “the Duellists” is the hands down winner, with the '70’s “3 Musketeers” and sequel coming in second. For Rennaisance warfare, Depardue’s (sp?) “Cyrano” had some excellent scenes. But the all time greatest and most realistic sword fights are in Kurosawa’s movies, especially 7 Samurai.
Just a quick note, by the way, on Star Wars: Although a lightsaber is very similar to a sword, it’s a different weapon, and a lot of the good parts of the Star Wars saberfights were the parts which emphasized the differences. Most notably:
The weight of the blade is negligible or zero
Any hit is guaranteed to maim or kill
The blade is “all edge”
Of course, the Star Wars movies had the best lightsaber duels of any movie, but that’s not saying much :).
There’s a toss-off of a film called Without A Clue starring Michael Caine and Ben Kingsley that ends with a really exciting swordfight if I remember right. (Haven’t seen it since it was in theaters, nearly 15 years ago.) It’s a comedy based on the premise that Sherlock Holmes was a buffoon and Watson was the brains of the operation. A pleasant little rent if you’re into that sort of thing.
Not that this is especially good, but it hasn’t been mentioned yet and it’s different: At the end of Young Sherlock Holmes, a guy with a sword takes on a guy with an oar.
Also keep an eye out for Cornell Wilde; he was graceful, athletic, and in his youth qualified for the Olympic fencing team.