Onimusha - PS2
I have been a Kaneshiro fan since before the game's release, so this was a real treat for me. I played it over and over, in Japanese with subs. <IMG SRC="smilies/smile.gif" border="0">
The most perfect 2D fighter ever created. Nuff said.
Runner up: Lunar 2: Eternal Blue Complete
I just felt I should mention this game too. It was hard to chose Fatal Fury over this game, but I did since MotW is the definitive 2D fighter, while L2 isn't the definitive 2D RPG.
If Grand Turismo 3 was the first title in the series, I would give the award to it. Unfortunately, GT3 is only a graphical overhaul with minor physics updates. Still a great game, but lacking innovation.