Linkage! You have anything to add, then Email me and convince me of you worth ^_^
The Bolter and Chainsword
The ultimate Space Marine forum. 6000+ members at time of writing, if you like anything in Power Armour then this is the place for you (including Chaos and Sisters of Battle) If you're looking for me, then search around for Dasleah in the Chaos and Liber Astartes forums. Oh, and be good or you'll be Kurganised ^_^
Deathguard.org
An incredible site for those who like their Chaos Space Marines all decayed and rotting (with bits of purple in good taste) Run, owned, and created by Ryan Powell, who also moderates on the Bolter and Chainsword as kenshin138. Give him a look and join the long line of those people who want to kill him and extract his painting skills from his essence.
The Jungle
This site is nothing short of amazing. It's the kind of site that when you decide to start one of your own, you are both intimidated and inspired by. If you even remotely like 40k in any way, then check this out. Articles like no tommorrow, themeing up the wazzoo, PLUS the redhead. Can't forget her, can we? ^_^