Breath of the Wild in portable form for the Switch...
Twilight Princess HD for the WiiU (do not judge me)
Killzone Shadowfall made me get a PS4, but Bloodborne was the first real "system seller".
I got an X1 just so I could bash it and not be a fanboy...and Sunset Overdrive and Titanfall were fun.
PS3 was Metal Gear Solid 4.
360 was Fable 3
PS2 was Final Fantasy X
PS1 was Chrono Cross
Gamecube was Wind Waker
N64 was Ocarina of Time (I got the system before it though)
Genesis was just a system I had.
SNES was Chrono Trigger.
NES was my first console.
Gameboy was Mario Land
GBA was Golden Sun.
3DS was A Link Between Worlds
VITA was Uncharted Golden Abyss.