Below is the full-size image mockup I made for webchick to highlight the awesomeness of Drupal's (relatively) new stark theme, as seen in Drupal 7. You can download Stark for Drupal 6 as well, but it will be a nice way to quickly expose the underpinnings of Drupal's core HTML output.
(click on the image to view a larger copy)
I'll be working on at least one CSS-only theme for Drupal 7 over the next couple of months, and will hopefully release it to drupal.org by summertime. The transition from 6->7 is going to be awesome for themers!