I am sure this list will change tomorrow, so I am just going to go with spent the most time playing. At least remember playing the most. I could be wrong. I do remember playing a ton of Super Mario World, and I did not put in on the list.
PC - Quake 2
Atari 7800 - Pac-Man
NES - Super Mario Brothers
Gameboy - Tetris
SNES - Zelda Link to the Past
N64 - Mario 64
Sega Dreamcast- Soul Calibure
Gamecube - Super Smash Bros. Melee
Wii - Mario Galaxy
DS - Mario Kart
Playstation 2 - Grand Theft Auto
Playstation 3 - Sonic Unleashed
360 - Gears of War 2