I'm surprised that System Shock isnt in this list.

That game has permanently set my heart rate to an average of 80bpm. Shodan is still, to this day, the best video game villain! the way she evolved through the course of the game and grows to taunt you all the way to the end.

once you installed the game and did a sound test to check that all is working well the instalation plays an audio file from the game that says:
"look at you hacker.. a pathetic creature of meat and bones panting and sweating as you run through my corridors, how can you challenge a perfect immortal machine"
I had soiled myself before I even started the game.