Elliot Jay Stocks has updated and re-released his WordPress starter theme, Starkers.
Alister Cameron has written a simple function you can add to any WordPress theme that lets you intelligently and automatically force browsers to use your updated WordPress stylesheet.
Are premium themes open source? Should they even exist? Read When Premium WordPress themes and open source ethics collide for a good, controversial take on the subject.
If you think the idea of customizing a WordPress theme sounds painful you need to read this detailed, easy-to-follow tutorial on how to make a WordPress Child Theme.
Jeff Chandler gets at something I’ve been considering: WordPress themes that let users change the layout configuration from the admin might be a dead end. How many times do you need to change your layout? It’s neat feature—at first—but I think there might be a better way.
Dan Philbin of WPCandy gives the lowdown on WordPress Theme Frameworks, Child Themes and custom theme hooks and filters and how they relate to Thematic.
DesignMag has a good post up with some links to CSS layouts and Blank WordPress Themes but remember: if you’re starting with a Child Theme any WordPress theme becomes a blank framework.