blutheme

Feature rich theme with support for thumbnails, feedburner, twitter, widgets and gravatars
Crispp

Crispp is a minimal theme with clean lines that lets visitors focus on your content. A separate administrative section allows you to change the color scheme however you like. The theme is very flexible
Insanitious

Fluid width two-column theme with widgetized sidebar, gravatar and comment ready
Dusty

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