Color Theory for Designers, Part 1: The Meaning of Color

(from Lifehacker.com)

9 Common Usability Mistakes In Web Design

(from DZone.com)

Laws of Software Development

A collection of funny and interesting quotes about science and IT.

(from DZone.com)

10 High-Profit Redesign Priorities

He's one of the fathers of usability, so Jakob Nielsen's advices on web-design are always precious...

This article presents 10 suggestions on how to improve a for-profit website; anyway, many of them can be very useful for general purpose sites too.

Contains a link to an even more interesting set of articles about Writing for the Web.

(From dzone.com)

EDIT: corrected Gollum-style "precioussssss" ;-)