GTA 3 on PS2. Everyone wanted to have that game and it was an exclusive when it first came out.
Metal Gear Solid 4 on PS3. I know three people who bought the console just for that game.
Goldeneye 64 on N64. That game wiped the floor even with shooters on PC.
Those are the ones from the top of my head.
Official member of VGC's Nintendo family, approved by the one and only RolStoppable. I feel honored.