There's been a flurry of discussion on the WP-Hackers mail list ... nothing like re-design to bring pet peeves to the surface!
One new resource to emerge from all of this is the WordPress Interface Guidelines.
Rummaging through the pages there brought a few fine resources to my attention:
* Yahoo!'s "Design Pattern Library"
* Apple Human Interface Guidelines
* "Human Interface Guidelines" at WikiPedia
* GNOME Human Interface Guidelines
* KDE User Interface Guidelines
* At User Interface Engineering, Visible Narratives: Understanding Visual Organization and "Brain Sparks"
* Java "Look and Feel" Guidelines (Advanced Topics)
Also: Information Architecture Institute; Mark Boulton on Design Thinking