Five Games That Define You as a Gamer and/or a Person

[Xeon]

Game_God said:

Tetris
Zelda: LTTP
Secret of Mana
Chrono Trigger
Mario Kart
Goldeneye
Counter Strike
Gran Turismo 4/5
rFactor
Richard Burns Rally
BF3
Starfox
Racing Lagoon
Soulcalibur

5 games can't define me as a gamer, sorry...

Yeah, I quickly realized 5 is not nearly enough for me but had to stop myself for the sake of time.  Great list!