WordPress Blog Themes
One of the great things about using WordPress is the open-source nature and the many free themes that exist on the web. I am currently looking for a new three column theme to help organize my site a little better. Blogging Pro seems to be a good resource on all kinds of different blog topics.
The WordPress Theme Viewer is a WordPress sponsored resource that has a lot of different theme styles for you to choose from.
Updates: More themes here!