Thief I and II...the best games ever made...like Jacki Dice, I played the game when I was going through some hard times in my life, and Garrett (main character)'s dark, sad and yet uber cool personality resonated with me then...if he could make it through his hellish life, I could survive mine.

The gameplay, the atmosphere, the characters...everything about those games were perfect.
Dang it, just thinking about it, now I'm going to have to try to get my old copy of Thief running on Vista...which is NOT easy to do. ;P