Customizr is a highly customizable WordPress theme. This free theme comes with 8 skins and also includes a responsible slider (with a slider generator). The theme has an options panel, include multiple layouts.
Customizr has threaded comments for nice conversations between your visitors and 9 post formats.
The theme also includes a CSS panel and development tools. These dev tools include a developer dashboard that provides you with an overview of your theme settings and debug info. It is also possible to enable embedded tooltops.
The theme is well-coded and makes uses of WordPress hooks and even includes it’s own hooks API.