PSDTUTS has an article showcasing five genres of modern web design. Using the same layout, they’ve tweaked the visual style over and over again to demonstrate how to achieve a cohesive “theme” when designing for a certain look.
(Below: an example of their “grunge” theme)



Thank you for this fantastic article, you have re-affirmed my belief that the layout should take priority over the colour scheme/style during the design process! A website is only as good as the sum of it’s parts.