There's no good answer to this question, for me not even from a very personal perspective. So many games, so much variety, even if this was just for a single genre or mood or whatever, it would still be a very hard task to find THE best.
Anyway, off the top of my head, I could come up with four games that really impressed me and that are ranking very high among those I love the most:
Planescape: Torment - possibly the first RPG with a story that really interested me, a setting very much to my taste, knew nothing about the game when I bought it, had never heard of AD&D Planescape before, was intrigued by it ever since.
Forgotten Realms Unlimited Adventures & Neverwinter Nights - not for their original campaigns but for their 'moddability', probably the two computer games I spent the most time on, playing the hell out of graphically enhanced community modules with fine stories for years and years - each of them good in its own right and most of the time better than the official content, some with radically different gameplay, and the best with outstanding writing - plus these two game creators also allowed me to tinker with module building myself. What other commercial games allow people from all over the world to create and share their own stories, direct their own cutscenes, add their own graphics and sounds, to a certain degree even change the rules etc. in such a simple, comfortable and powerful way, without requiring any knowledge of programming languages? If you own one of these, you don't really need any other games anymore ;)
Psychonauts - because it's hilarious, weird and overall great fun, nevermind a few frustrations with the PC controls, this game is f***ing awesome! :)
But really, these are just a sample of my personal best games ever and I'd have trouble even deciding between them ...
Post edited May 06, 2011 by Leroux