My fave games are as follows

Killing Time [3DO]
PO'ed [3DO and PSX]
Road Rash [3DO]
Alone in The Dark [PC/DOS and 3DO]
Alone in The Dark: Jack is Back [PSX]
Doom [Source ports only]
Duke Nukem 3D [PSX/PC and Eduke32 Source port]
Duke Nukem: Time To Kill [PSX]
Metal Gear Solid series [PSX to PS3]
Rayman series [PSX to PS2]
TimeSplitters [PS2]
Gran Turismo series [PSX to PS3]
Amnesia: The Dark Descent [PC]
Oddworld: Abe's Oddysee [PSX]
Nightmare Creatures [PSX]
Silent Hill saga [PSX to PS3/Xbox360]
Tomb Raider saga [PSX to PS3/Xbox360 and PC]

thats all I can think of for the moment

EDIT: Am I the only person here who has/has had a 3DO?