Blender
Blender.org - Official Blender 3D Page
Blendpolis - German Blender 3D Forum
Blenderartists - English Blender 3D Forum
Blender Documentation DE - German Blender 3D Documentation
Blender Documentation EN - English Blender 3D Documentation
Blender Materials - Blender Open Material Repository
Blenderart - Frequent PDF magazine from blender users, free for download.
Blenderguru - Nice Blender tutorials
Free Renderer
Yafaray - Renderer using the Montecarlo approximations
Sunflow - Sunflow Global Illumination Rendering System
Indigo - Indigo is a physically-based unbiased render engine
Kerkythea - Kerkythea global illumination render engine
Luxrender - Luxrender is a unibased renderer
Radium - Radium is an unbiased metropolis light transport renderer
Toxicengine - Toxicengine is a global illumination renderer
CG Related
Deviantart - My deviantart homepage
3dtotal - CG Artists Homepage
CG Society - CG Site with forum
Evermotion - 3d Resources
Scifi-Meshes - Scifi-Meshes
Sci-Fi 3D - The Ultimate 3D Sci-Fi Resource
HDRI
Dosch Design - HDRIs and other 3D things
HDRIMaps - Buy HDRI probes online
HDRI Locations - Backplates for virtual car photography
Realtexture - HDRI Probes
Sachform - Professional HDRI Probes
Textures
Arroway - Professional Texture Resource
CG Textures - Free Textures
GIMP Tutorials - [DE] Tutorials für Texturen und Muster
Artists
Akta - 3D artists and programmer using Blender
Bertrand Benoit - 3D artist using the Indigo Render Engine
Martinsh - 3D and Concept Art artist with nice style
Pascal Eggert - Professional graphics designer and freelance concept artist
Thomas Suurland - Home of Thomas Suurland and THE blueprint directory