Chaos on the Sinclair Spectrum, from when GW made computer games.
Mario Kart original and Double dash, pure genius and a great laugh after a couple of pints.
Street Fighter II Turbo, chess with knuckledusters.
Silent Hill 2, a dirty, disturbing headfuck of a game.
Zelda Ocarina and Wind Waker, the joy of finding something new is brilliant.
Timesplitters 1, 2 and 3, tongue in cheek fun with a gun. Any game where you can play an Elvis impersonator has to be cool.
Castlevania Symphony of the Night. Perfectly paced exploration, bags of atmosphere, cracking soundtrack and the upside down castle secret area.