The fantastic Thesis theme from DIY themes just keeps getting better and better. Version 1.3 sees the addition of two significant new features, plus a lot of minor tweaks and improvements to help you build a more secure, dynamic website.
The theme also features a new html framework selector allowing you to select either a fixed page width, or full width framework.
The second key improvement is the theme is now completely adorned with hooks that you can use to inject content into specific places in the markup. Hooks are important aspects with customisation, because they allow you to make forward-compatible changes to the theme without touching any of the core code. Thesis now contains 31 different hooks that you can use to add and subtract content all over the theme (for example ads, design embellishments, plugin compatibility, etc).
More information and theme features can be found here. Or you can try a demo and purchase the theme here.