Like many others have said, Planescape: Torment has one of the greatest video game stories of all time, but (and I hate to say this because I know how much P:T fans would disagree) it's in dire need of a remake. The combat flat out sucks, and the exploration can be a little slow.

Still, the characters are amazing, the narrative is excellent, and the world is interesting in ways that make other video game worlds feel boring. Buy it for sure, but don't be ashamed if you have to knock the difficulty down.