Mindboards - Building a LEGO Mindstorms NXT Community Brick by Brick.
PlastiBots - LEGO Mindstorms Robotics, DIY Hacks and Other Stuff.
TechnicBRICKS - The amazing world of LEGO® Technic constructions.
The NXT STEP - The NXT STEP Blog brings together news and information related to the LEGO® MINDSTORMS® NXT system.
Modelbuildersecret's Weblog - created by Mariann Asanuma, a former LEGO Master Model Designer and now a Freelance LEGO Artist and Author. Checking out her blog dedicated to all things LEGO. ;)