As Dries said in a State of the Drupal, "There will be 7 Drupal sites created in the next minute.... 4 of them will look bad" [sic]. The solution is to enable easier theme discovery and better tools for theme developers! If we want new Drupal users not to end up with ugly sites, then we should offer clear, concise options to discover a theme that fits their needs.
Suggestions on ordering the data:
Categories:
Width - fixed or fluid (resolution ?)
Number of Columns - #, adjustable
Search Bar - included/not
Color Module support - (or in general, reference related modules)
Derivative work of: reference existing themes
Discussion: Voting and Reviews in Theme Categorization && Module metrics and ranking
Suggested Audience: (Art & Photography, Corporate, iPhone, etc)
Text direction (Right-to-left, left-to-right, or both)
Color scheme: Light on dark or dark on light (or both)
Is it a base theme? (suitable for modification)
Does it have print.css included?
Current places to find themes
The most recently contributed themes: http://drupal.org/taxonomy/term/15
Most recently changed: http://drupal.org/project/Themes/date
List Alphabetically: http://drupal.org/project/Themes
Base theme comparision (with more categories): http://drupalstaging.com/starter-themes/starter-theme-comparison.html
Defining a brighter future for themers and theme users
D.O themes can become an element of the site broadening our social network to include people who like web design templating, allowing users to make beautiful designs and have an easy start to creating derivative designs. Active theme developers could maintain a front page of themes just like the core d.o people maintain the d.o front page and og team:groups.d.o. Flickr serves the needs of photographers, deviantart for artists, but what about a section of Drupal for everyone interested in making beautiful sites, but not interested in Drupal module development.