Someone highlighted a long list of the MetFilter threads on Katrina, and someone else added the comprehensive, longer list (ninety-three and counting) to the MeFi wiki.
Meanwhile, AZ links to two interesting New York Observer pieces on, respectively, how the Times-Picayune managed to do such a gripping job of covering the disaster (apparently, the blog post on the NOLA blog concerning the broken levee was in fact the T-P breaking the news) and on the remarkable media meltdowns that have marked the televised coverage.