Finally, someone found a clean way to do three-column fluid layout with XHTML and CSS. This solves just about every three-column layout problem I've ever had. It fixes the visual elements, keeping the footer at the bottom of the page no matter which column is the tallest, and resizing without the elements running into each other.
The visual side of this has been done before – especially with tables! – but what is most important about this version is that is using clean XHTML, with no extra non-semantic markup needed, though one div tag can be added for increased browser compatibility. What's more, it allows a good struture: when it's unstyled, it displays the heading and content before the navigation. This makes things easier for people with screen readers and older browsers.