One Column Themes
WP Pix is a one column theme with no sidebars. The theme can be use by photo bloggers. The theme comes in with two different page templates one for displaying a blog and another for displaying portfolios.
Two Column Themes
Happy Cyclope is a 2 column widget-ready theme. The theme is easy-to-customize, and displays the category pages and archives as lists.
Big Brain is a two column widget-ready theme. As the name suggests there is image of big brain in the header. The theme also uses bigger fonts for post titles and content.
Ndomche Summary is a two column theme. The theme has a grid based style and has only been tested with WordPress 2.5 and above.
Aurora is a two column widget-ready colors. The theme makes use of dark colors.
Elegant is a pleasant looking two column theme. The theme is widget-ready and is made up of different flavors of the blue color.