Sephiroth vs Angeal and Genesis...possibly the best in any FF game, he owned them both while talking shit  "hmph, is that the best you can do?"...that was awesome.

Onimusha 3 intro is one of my all time favourite

that's a tough one as there's so many to choose from. I like the Devil may cry 4 one between both main characters. I also liked the MGS4 final fight. lol

Gotta give it to Zelda : Ocarina of Time

The LAST FIGHT after the castle collapses

Still one of my favorities.

2nd place: Mega Man II - Dr. Wily fight

Yeah. Old school

THAT scene, in Xenosaga 3.

Everyone who played the game will agree with me, everyone who didn't, and says something else, is wrong.

Kingdom Hearts 2 Final Boss 

From beginning to end that fight is just epic.

I can't remember that one. It's been forever since I played that game. lol

This one:

http://www.youtube.com/watch?v=xMJ2Z8cNsxc

Seriously, the fight between Zero and Sigma (MMX4) and the last fight in Yakuza are really good.

rpg fights?  hmmmmmmm

the best fight ive seen in a game was solid snake vs liquid ocelot on the carrier at the end of metal gear solid 4.

^This