Crimson's 'freeze frame' attack on the home intruders in the first episode of Season 2. There is about one fight scene per episode, but this instance is definately the most creative.
Crimson and Disel's rematch at the end of Season 2. That's some genuine fight choreography, right there!
Bruce defeating Infernus in War Zone Part II. Is this really the same guy who started crying because of poor restaurant service in Season One?
The last episode of War Zone is full of these; the fights are excellent.
The Reality Show
Letitia's defeat of both Shondo (a professional cage fighter) and Andrew (a wrestler) in "Battle Dome"
Underdog Lina's victory over Shondo and Andrew in the finale.
Tell me you didn't thrill a bit when the Fates brought the other paladins back and told Lina that they were her army. I dare you.