Themes to Consider as starting points: Drupal 5

5.0 Themes

Allegedly Foundation theme is also 5.0, and "the best starting place" according to someone at DrupalCampNYC...

(+ means included in Agaric's site recipe generator)

• http://drupal.org/project/bluebreeze - based on Zen ("the starting point theme") but farther along to looking awesome

• http://drupal.org/project/sinatra - A very solid rewrite of Bluemarine

Consider:
+ http://drupal.org/project/aberdeen
Liquid CSS layout (tableless)

• http://drupal.org/project/amadou
  Amadou is a three column layout based loosely on several different templates available on openwebdesign.org - it is sort of a mutt theme.

• http://drupal.org/project/golden_hour (I just like the name)

• http://drupal.org/project/stylized_beauty (See its CSS dropcaps)

• http://drupal.org/project/sympal_theme
  A base theme. A framework for CSS themes. A theme developers theme.
  If you have been following some of the recent CSS and webdesign trends, you might have noticed the trend slowly bending towards semantic correct designs. As it should have been from the start.
  This means that you don’t just design a site, but really build it. Starting with a good blueprint, which results in a good foundation.

• http://drupal.org/project/zen