Links to some of my favorite sites:

BtVS Writer's Guild - Resources for writing in the Buffy/Angel universe

Boils and Blinding Torment - Buffy site with episode recaps and lots of other fun snark

Television Without Pity - Detailed reviews of TV shows including BtVS and Angel

Buffy Canon vs Fanon - Canonical character and vampire info for BtVS and Ats

Blood Screaming's Timeline - Timeline of historical events for Jossverse's Fanged Four

S/X & Violence - Essays and info about writing the Spike/Xander pairing

All Things Philosophical on BtVS and Ats - Metaphysics. Morality. Ethical quandaries.

BuffyWorld - Episode guides with trailers, summaries and screen caps.

Giles' Sunnydale Apartment - Map and photos showing the layout of Giles' apartment in Sunnydale.

Mad Poetess' Screen Cap Sources - Links to good screen cap sites.

Buffyverse Music Video Database - Buffy and Angel vids.

Firefly Screencaps - Excellent screen caps from all episodes.

Better Buffy Fiction Archive and Better Buffy Fics Bookmarks - Permanent and temporary archives for the BetterBuffyFics list at YahooGroups

Buffy Fiction Archive - BtVS and Ats archive

My Immortal Beloved - BtVS and Ats slash

Author's Choice - BtVS and Ats Author's Choices stories

Campfire Tales - BtVS and Ats horror fic

Slashing the Angel - Angel slash site

GilesSlash Archive - Giles slash site

Wish I Could Stay - Giles fan fic site (Site seems to be down)

Loaded - Giles/Oz slash site

A Demon's Heart - Doyle fic site

Our Armageddon - Spike/Angel slash zone for the BtVS Writer's Guild

Peaches Won't Be Happy - Spike/Wesley slash site

Double Indemnity - Wes/Lilah site

Gunn/Wesley Fanfic Archive - Gunn/Wes site

Deconstructing Wesley - General Wes site

Wesley Fanfiction dot net - Wes fanfiction of all varieties

Yes!Wes - Non-slashy Wes site with an emphasis on the Cordy/Wes 'ship

Wes Visions RPG - Reader's Guide

Reading - Individual Author's Sites

Magpie's fan fiction

The Brat Queen's Angel fan fiction

Wolfling's Lair - Wolfling's BtVS and Ats fic

Pointy Stakes - BtVS and Angel fan fiction by the Mad Poetess

Flaming Muse's fan fiction

Jane Davitt's fan fiction

JustHuman's fan fiction

Subtle Salvation - Ladycat's Buffy and Angel fan fic

Gila's Cave - James Walkswithwind's Angel and B:TVS Slash

The Crypt - Byrne's fan fiction

Between the Stars - Vi's fan fiction

Xanderdreams and Spikemares - Cici's fan fiction

Shrift's Angel Fan Fiction

Wackiness Ensues - Rubywisp's Buffy and Angel fan fic

Anna S's Buffy fan fiction

Educated Guesses - Pet's fan fiction

Stranger Things - Esmerelda's series

Love That Dares - Jenny's Buffy/Angel Slash fic

Octaves of the Heart - Chrislee's Buffy and Angel fan fic

The Clockwork Vampire - Spirit's Clockwork vampire archive

Saber Shadowkitten's Buffy fan fiction

Shadowscast's Buffy fan fiction