Sky Networks:
Technical stuff.
Greg and David's C64 Web Page:
Lots of resources.
C64 Game Guide:
Excellent guide.
Commodore related links:
Good C64 links listing.
Commodore 64 Art Gallery:
Guess what....
The SID Homepage:
Essential for C64 music.
Project 64:
Documentation archive.
MJK's C-64 Page:
Hardware information.
Creative Micro Designs:
Hardware manufacturer
Maniacs of Noise:
Great 64 musicians.
Censor Design:
Great demo-coders.
C64 Picture Gallery:
More art.