Fanfic With Footnotes
Jo and Ryo, collectively. They're out of control. Josh/Donna and some nice CJ.

Kim
Quite a bit of Josh/Donna including a series that really needs to be finished.

Spark Girls
An impressive collection of stories, slash and het. Everything here is fantastic. Home of Violet and Cinnamon.

Our Boys
An archive of some of the best stories out there. Slash heavy.

Wednesday Night Rants
Sary's fantastic post-episode stories. Great handle on dialogue. Jenny's Archive
Huge, huge collection of stories. All pairings, all lengths.

You Guys are Just Fucked . . .
Sabine's wonderful stories.

The Underground
Punk Maneuverability's equally wonderful stories.

Seanachais
Perri's work. New, beautiful design.

Nomad's Realm
Talk about a multi-fandom author. And speaking of multi-fandom, check out Donna the Vampire Slayer. Trust me on this. I was skeptical at first, too.