Victorious Boxer 2: Japanese version. PS2
Reason: The career mode is by far the best in a sports game ever. A game that isn't graphically special but the gameplay is and it runs at 60fps. Replay value is near infinite as you can compete in any weight class, go up and down in weight during a career and hold weights in different weight classes and in different fictional federations. You have to make weight for fights, train for specific fighters, etc. Still the best sports game, overall, that I've ever played. The only reason have my computer tunneling ISOs to my PS3 to play PS2 games as I have a launch date PS3 for the PS2 hardware in there. 60fps to boot.
F-Zero GX: Gamecube
Reason: I don't think that the futuristic racing genre can be improved upon this. Even Nintendo were to just simply update the graphics on the Wii-U, I'm buying this and the system that day. My only reason for having Dolphin on my computer. Everything else was icing on the cake. Perfect control, perfect framerate, perfect music, just a perfect game. shyt makes no sense how piff it is.
Perfect Dark: N64
Reason: A plethora of options, weapons, maps for multiplayer that to this day, still hasn't been touched. Plus there are bots. I could play forever.