Screw Sega for putting it on the Xbox, that was the one system I didn't own last gen -_-
Jet Grind Radio was THE game for cel shading, it's the first one I played, actually... looking at Wiki now,
"The first 3D video game to feature true real-time cel-shading was Jet Grind Radio (2000) for the Sega Dreamcast." Awesome, I get bragging rights now