Stylevantage is a free three column WordPress theme. It is compatible with WordPress 2.5+ and has native Gravatar and tagging support. Comes in three different colors (orange, blue, green).
Demo (orange default): http://demo.themelab.com/index.php?wptheme=Stylevantage
Link: http://www.themelab.com/2008/05/11/stylevantage-free-wordpress-theme/