Some of my favorite premium WordPress themes.

Template Monster provides high quality themes and excellent after purchase support.

The Thesis Theme for WordPress is a high-quality template system that you can use to improve your site immediately. Thesis boasts the strongest SEO of any theme on the market today thanks to its expertly-coded HTML + CSS + PHP framework.
Theme Name: Thesis
Cost: Starts at $87
Support: Lifetime theme upgrades. Complete access to the Thesis forums. [...]

These themes “blank” making it easy for anyone to add their own logo and match their blog to an existing website layout. The theme is available in both 2 and 3 column layouts.
Theme Name: Blank WordPress Themes
Price: Free
Support: None
Where to download: Visit their website to download.