I generally get the impression that Mac users stick to their computers longer than PC users. No wonder there are lots of sites about how to put these old machines to good use.

• Low End Mac is a huge and indispensable site. Whenever I buy a new old Mac, or try to decide whether I should buy it, I look it up here.

  The mission of Low End Mac is helping users get the most value from their Macs and Mac clones. We're not concerned with having the fastest, most tweaked out computer possible. We're not concerned with keeping ancient Macs in use long after they've become bottlenecks. We are concerned with value: getting the most use from your hardware for the money, whether that means an upgrade or a newer Mac.

  Dan Knight, the publisher of this site created the Open Link Policy, a policy I fully subscribe.
• the pickle's Low-End Mac FAQ
• The Vintage Mac Museum by Motohiko Narita is “9inch/mono Display 68000 Vintage Macs ONLY”. It features screenshots of all the systems compatible with this kind of Mac, and of an incredible number of programs and games, including very old versions of Photoshop and the infamous MacPlaymate.
• ANT WORKS Company's Home Page: In the Icon Garden, there are icons for nearly any Macintosh model.
• EveryMac.com is the complete guide to every Macintosh, Mac Compatible, and upgrade card in the world, with technical, configuration, and pricing details. Part of the site is now members only (as far as I could find out, only the photo gallery), membership is free.
• Apple and the History of Personal Computer Design by Ed Tracy
• Macintosh Museum: Some information (used market values) has not been updated since 1996, but it's a good overview of every Mac built before 1997.
• The Mac 512
• myoldmac.net is a bilingual German site.
• System 6 Heaven

  System 6 is an operating system that needs about 1 megabyte of hard disk space to be able to print, connect to a network, multitask, deliver wysiwyg, handle millions of colours, and carry a decent GUI, etc. etc. The only really interesting enhancements that were added to the later versions of the mac operating system were 32 bit addressing and lousy virtual memory management.
  System 7.x, 8.x and 9.x are basically all the same stuff but more and more filled with bloatware and high level code to make sure that people would keep on buying new hardware because their old computers wouldn't run the new software fast enough. This is a process that began with the release of 7.0, an operating system that seriously slowed down a generation of macs that were running pretty snappy before.
  Considering all this I think one can safely say that System 6 is the best macintosh operating system ever written, because it did all the major tricks without needing 64 mb of RAM and a 233 Mhz processor, while being basically faster and more stable.

• Home Page of Gamba