Great question!
I probably played EA Sports NHL Hockey for Sega Genesis the most. I bought every version each year, but probably played 93 and 94 the most.
Really old school was Yar's Revenge on the Atari 2600.
A little later was Hitchhiker's Guide To The Galaxy text-based game for my Commodore 64.
In the arcade I mostly played Tron and Mrs. Pac-Man (fast version) as I got the most for my money and could go very far. I also played a lot of Dragon's Lair and Afterburner.