I have to go with the original "System Shock", although #2 is great as well. Fantastic article by the way. Thanks for the link.The Madman said:System Shock 2
It's challenging, has a great story, well written dialogue, and while the voice acting doesn't always nail it, when it does it's spectacular. It also does an amazing job of creating an oppressive atmosphere, which is something I find most modern horror games lack. Horror isn't about jump scares, being startled isn't the same as being afraid, horror is about creating a sense of unease and challenging the audience's feeling of safety either through effective atmosphere or through a chilling narrative. Then just to top it all off System Shock 2 also got two of the best villains in the entire gaming genre, SHODAN and The Many.
There have been entire articles written about how damned well done SHODAN is, that's how good she is. Heck, I'll link my favourite: The Girl Who Wanted To Be God by Kieron Gillen, who retired from game journalism and now works as a writer for Marvel.