easy one for me -
Bard's Tale
battling for runner-up: Pole Position and Mario Brother, both on Atari 7800. Wolfenstein 3-D would get honourable mention as well. Text games and Myst place near the top as well.
Never have played more than 5 minutes of quake or any of its sequels, but did my share of Doom and the 'thousand WAD file' expansion package though. Rise of Triad always entertained me more than Doom or any of its other clones; have to love 'dog mode' and the all-mighty hand that smotes anyone down.