The Haven for FBI's Most Unwanted
The Haven has great spoilers and fan fic; updated everyday
Squirrelsnest or the PA X-Files Homepage
Squirrelsnest also has spoilers that come from various places. She also has games, quizzes and pictures related to the X-Files.
The X-Files Experience
Autumn has a great reviews page which is updated every Thursday.
Tiny Dancer's Page
TD also has a reviews page along with episode transcripts that you can't possibly find anywhere
else.
Gossamer
The Gossamer archives have lots of stuff, but they don't update very often.
The Official X-Files Page
This is The official page. It has a great episode guide complete with pictures and clips from the episodes.
Episode Fiction
Ever wonder what could have happened during or after the episode takes place? Well if you have, then this is the place to go for post episode fan fic.
Ephemeral
This site is an auto archive, meaning that as soon as the stories are posted at alt.tv.x-files, they are entered into this site. So, it's updated very often.
Song-Fic Archive
This site includes fan fic that are based on songs. Very cool.
BADFIC The XF Hall of Shame
This is the site for the really bad fan fic that people write. Some of them are really funny!!
Anti Fowley Mailing List Homepage
Do you hate Diana Fowley? Do you realize that halfway through an episode that she's in, you've been cursing her off the whole time instead of paying attention to the plot? Is she on your deathlist next to that damned bee you saw in the movie? If you answered yes to any of these questions, you have to visit this site! (** Note: the above link is to the non-frames version of the site, which I think is much more easy to navigate. However, to choose a frames version, you can go to the very first page, http://members.tripod.com/~antifowley/.)
You might not know who Joan Rivers is, but you will once you visit this site. This is a pro-Gillian Anderson, against JR's incredibly bad insults site. *WARNING*- PG-13 language, may not be of interest to some people, but personally, I think it's hilarious. However, it's unlike any other "hate" page I 've ever seen- very harsh. And I don't know if it's all true, but I'm sure she deserves it.