Answer = zero, If you mean strategy and FPS games. Some role-playing games have generated similar fan communities.
Heck, even *I* have left my Shrine T'Fear page up, though as far as I know no one has linked to it :)
http://homepage.mac.com/qmorris/.Public/www/marathon/mara.html
Bungie has scored big in the lasting interest column for the two games you've mentioned, and it's in large part due to intricate stories behind each. We should also mention that map-making tools and a satisfying multiplayer experience have also helped.
-David