It was between Super Mario 64, Resident Evil, and Tomb Raider. I ultimately went for Tomb Raider. Like others, I love the controls and how methodical everything is. One of the few games I play through every year, guaranteed.
Resident Evil is still the peak of the series for me. Experiencing this at release was incredible. The atmosphere and sense of discovery as the story unravelled was unlike anything I'd come across before. Don't think they've ever matched that feeling since, which is probably why I hold this entry in such high esteem.
Super Mario 64 - the first time using a joystick to control Mario was mind blowing. Still loads of fun to play today.