The Bolter and Chainsword : By far and wide the best Warhammer 40000 Resource site about Space Marines. They support the Sisters of Battle, Chaos Space Marines, The Inquisition and Adeptus Mechanicus armies.
The FTW Blogger Group is a group of bloggers who share the same idea of promoting Warhammer 40k and the hobby in a positive light with our individual 40k blogs.
House of Paincakes is another community network that is here for those that want gaming content without feeling the need to tow the line and self-edit.
Bell of lost Souls : An excellent site for wargaming in general. This site has hundreds of articles and commentaries with two or three published every day . It is also has one of the most comprehensive blog networks on the net with respect to gaming.
Imperial Literature : This site is dedicated to publishing quality fan fiction revolving mostly around the worlds of Warhammer and Warhammer 40K.
Statue Forum : The only forum dealing with the sculpting and collecting of pop-culture statues I enjoy visiting. In fact it is the only one worth visiting in my humble opinion.
My Battalion is a very popular source for tactical board gaming. They strive to bring you all the latest and offer you a community to share ideas and concepts.
Beasts of War : Another excellent site for wargaming. It has articles, reviews and modelling advice in written and video formats, besides many sub-forums on everything that has to do with wargaming under the sun.
Comic Art Community : This is were I go when I need reference material for my superhero sculptures. The site is packed with comic book artwork of all types and genres.
Wargamersworld : I doubt there is a better bits shop on the Net. Not only does this shop offer affordable prices it also gives excellent discounts to regular customers. I also know for a fact that the owner is as honest as they come and truly interested in offering good service.
Going on Campaign is an unofficial rulebook and source guide for campaigns in Games Workshops Warhammer 40k. It is by far the best and most comprehensive campaigning resource centre for all dedicated fans.
Il Nana Nefasto is an independent painter site. It has great reference pictures for Dystopian Wars' models and Spartan Games in general. There are also great tutorials and miniature artwork to admire.