Waterloo is a generic theme I developed to contribute to the Drupal community. As a contributed theme, it is designed to be usable on a variety of sites with a variety of configurations. At the same time, it is designed to be simple and easy to set up. There are six versatile regions, and three colour choices.
Developing a theme for general use is a lot different from developing themes for specific sites. With a specific site, you only have to consider one particular implementation set up. The menus, search box, and other elements are not going to move around. With a contributed theme, this completely changes. You have to consider what will happen if users place blocks in unexpected regions. It was also importnat to me to provide an implementation for all core modules, including forum (I don't know of any other themes that provide a custom forum implementation).
Waterloo is availble for download on drupal.org.