I really enjoyed this article, though it could have gone further in depth about some of the advances made in the 90's. The 80's coverage was pretty good, and the history of PARC and even before was excellent, but it abruptly ended with Windows 95 and OSX, and left out a lot of the *nix GUI "experiments" from the mid-90's. It really made me want to learn more, especially about NeXT and BeOS (which I have actually used, believe it or not!) and their history. Thank God for Wikipedia! Oh, and there's also a decent screenshot archive at http://www.aci.com.pl/mwichary/guidebook/interfaces.