They are a good starting point for creating your own layout if you do not want to create one from scratch.
Contented Designs makes the templates it creates availible for anyone to use for free and are all valid CSS and XHTML 1.0 strict compliant. They've been cross-browser tested and are free to use and modify. Shunro's ports make it even simpler for CakePHP users to drop the templates in quickly and easily. You can check out previews of the designs on his site.