The Ultimate Macintosh -- The best site for links to everything Macintosh. It claims to be the "biggest, ugliest, and most useful Macintosh site on the web." All my favorite Mac sites are listed here, and hundreds of others, indexed nicely with short descriptions.
(Dan has suffered tendinitis from computer overuse--if you feel pain in your wrists or arms when you use your computer, check these sites, and don't hesitate to see a doctor!)