BugMeNot.com, which gives you a username and password so you can bypass required registration on annoying sites.
The End-All Guide to Small-Screen Web-Dev. “It takes one gigantabig tutorial to teach you how to build sites for all those itty, bitty devices.” A great last gasp from Webmonkey.
IE7 suite (mirror)—using CSS to fix IE/Win’s CSS rendering bugs. Bloody brilliant.
List-o-matic Dreamweaver extension, based on the fabulous List-o-matic, and the Dreamweaver 7.01 update, which fixes speed bugs, CSS rendering glitches, and adds back the Timeline feature.