The Evolt.org Rebuild: The HTML and CSS is a good read. They decided to show that you can build a web page that is standards compliant and more importantly, accessible and compliant in everything from lynx, links, netscape 3.x, iCab, mozilla, netscape 6, opera and IE. They figure they got close to 100% conformance with all the browsers (graphical ones anyway), but are HTML 4.01 Transitional and CSS 1.0 compliant.
A webpage that looks good in whatever you view it in, doesn't have any stupid "this site only viewable in IE" messages, or any silly tricks like stripping off all CSS for non-IE browsers.
Now, throwing the site through the html validator doesn't render perfect results, but I think the results are worth using a single depricated element ("MARGINHEIGHT").