Well, every other forum has one, so I figured I'd get this one kickstarted.
Usability Grand Poobah Jakob Nielsen
Usability Views - Article Aggregator
Usability News from Wichita State University
Web Developer's Reference Library- Usability Contains quite a few book excerpts.
Jeffrey Zeldman's Daily Report
Joe Clark's Building Accessible Websites (serialized.)
Dive Into Accessibility
Validate your accessibility guideline compliance with Bobby
Web Accessibility Initiative
WAVE-Web Accessibilty Validator
Jesse James Garrett- featuring "The Elements of User Experience" diagram and "Visual Vocabulary" sitemapping standard.
Adam Greenfield's v-2 Organization
Christina Wodtke's Elegant Hack
Boxes and Arrows
A List Apart
Sigia - L
"TheList" at Evolt
And last but not least...
I know it's incomplete, but it's a start.