Here's a small sampling of the blogs I read. This page was created using PHP and an XSLT doc to grab the first three posts of the RSS feeds and translate to HTML. jQuery is used for the AJAX call and animation. This is just a rough pass as I've just started learning jQuery and XSLT.
37signals
37 Signals is the company behind successful webapps Basecamp, Highrise, Backpack, and Campfire and the creators of Ruby on Rails. Their blog talks about design, the development process, and business issues.
A List Apart
Requisite reading for anyone wanting to learn the joys of hand coding xHTML/CSS. Also publishes insightful articles about doing business and the state of web development.
Vitamin
Articles about development, design, and startups from an all-star lineup of contributors.
CSS Beauty
An aggregator of blog posts about CSS development.