Qui-Gon jin & Obi-Wan Kenobi VS Darth Maul (Star Wars Episode 1) 9/10
the fight in Star Wars Episode one is good but they ruined it by cutting and intersplicing the sequence with all the other stuff that was happening - plus the way Maul dies was pretty crappy.
Neo VS Agent Smith (The Matrix) 9/10
Even though Reeves and Co only had a few months to train, they pulled it off - its such a shame that their fighting styles were dumbed down in the later movies.
If you look at the top 20 fights of all time, you'll see Jackie Chan is in almost all of them.
My personal favorites are:
Police Story 2 - the bit in the playground where Chan has to face lots and lots of hoods.
Meals and Wheels - The fight between Chan and Benny the Jet was superb, but the re-match in Dragons Forever wasn't as good, IMO.
Fist of Legend - every fight is very good.
there is a Donnie Yen movie that I like too but I can't remember the name of it, but its meant to re-define what is meant by hyper-kinetic fight sequences.
Legend of Drunken Master or Drunken Master II (uncut Chinese version, not the hatchet US version) is perhaps the best hyperkinetic fight and is yet to be rivalled.