Some cool games with moments worth remembering:
Alien Breed: Tower Assault - you're running in military base full of aliens (like from Aliens movie), no support, low on ammo and mission objective on some level is to find keys, open doors, find detonation switch and start countdown. Finally I got there, pulled switch... then all screen went red-glowing, alarm sound started buzzing and female voice announced: "30 seconds to self-destruct". Of course exit door was on the opposite side of level, so i started running like mad, alarm buzing, screen glowing, aliens everywhere, finally ran into long corridor, saw only few aliens ahead, fired on them... and instead of shooting hear only clicking sound: no ammo clips.
The horror I tell you... @_@'
Diablo 2: final animation with Dark Wanderer and old man in asylum was great. And many priceless moments while running away from champions with lighting aura, a few points of light and mana, no life potions, no town portal and map full of monsters in every direction -_-'
Baldur's Gate 2: as mentioned before, Irenicus is a cool badguy. Also all the "romance" scenes with party members, including special music and dialogs, were unexpected, refreshing and nice contrast to monster-slashing quests.
Carmageddon 2: mission with big truck for the first time was a shock. You start a race with only one opponent, at night AFAIR, and see only a dot on your radar. Well, you drive on road straight ahead, visibility bad, dot approaches from front... and then you see for a second huge truck that smashes your car without stopping and drives away X_x'
Pinball Fantasies, Pinball Illusions, Slam Tilt - all animations and mini-games triggered after hitting with ball some hard-to-reach table elements, they were even more enjoyable than pinball itself.