The COMPET-N ( http://competn.cjb.net )
 Public Doom Archive of the Non-Gods //  Arno Slagboom ( ftp://lmps.dhs.org/pub )
 Doomed Speed Demos Archive
 Présage  - Albert Valls / Gonzalo Perez de la Ossa
 Tools Assisted Demos
 BahdKo's Deathmatch Site
 Ftp.cdrom.com
 Ledmeister
 Cyberdreams / Dense13 / Vrooomer

Others:
 Doom Speedrunner's Message Board
 fx  -- Inchfall
 Coop-N
 Andy Olivera
 Stuart 'Yeti' McKendrick
 Jason Yasuko
 Frank 'Jesus' Siebers //  Reality
 Jason Henry
 Yonatan Donner
 Anders Johnsen
 Realm of Chaos
 Brian Lewis
 Rich Sham
 Radek Pecka
 Ilkka 'Mineral' Kurkela
 Ugwad
 Brad 'Vorpal' Spencer
 Doom Honorific Titles 5 -- Frank Stajano // Hall of Fame
 Doom Honorific Titles 6
 Doomaniax
 Team Insanity
 Wim 'The Mole' Vanrie
 Clan ZAP -- Marijo 'Sedlo' Sedlic
 Clan Nightmare
 The Doomers
 Doom-CZ
 DeadSimple
 Brotherhood of Vengeance -- Kim 'Zokum' Roar Foldøy Hauge
 Quake Done Quick
 Doomworld -- forgot all about that one, huh?
 Uwe Girlich
 Doomster

Major FPS demo sites:

 XSReality -- FPS // Demos  -- IE only
 XSReality -- Counterstrike -- IE only
 Clanbase
 Challenge-tv
 Sean 'Cache' Shelton //  Cached.net  // Cached's ftp
 Quake Speed Demos Archive
 Quake Done Quick
 Challenge-hl
 Stayne's House of Demos
 Cineplex