http://www.deviantart.com -
Great site with digital artists from all around the world. Some particular
favorites:
Stacy Lee - more digital art by a friend from college
Julian Bever - neat sidewalk art playing with perspective
http://www.good-tutorials.com
- good index of Photoshop, etc tutorials
Firefox - this site optimized for Firefox.
These two came from a link trade, so I don't really know what to say about them...
http://www.readingsteps.com
http://www.xdan.com