Web Style Guide
The Web Style Guide has a lot of great info on building web sites, but this paragraph just pisses me off:
Web Style Guide: One of the visual properties that Cascading Style Sheets are meant to describe is how elements are positioned on the page. Style sheet positioning allows designers to set margins, to position text and images on the page relative to one another, to hide and show elements, and to stack elements so they overlay one another. In theory, style sheet positioning should provide all the design control needed to lay out visually appealing and legible Web pages. In practice, however, browser inconsistencies have rendered style sheet positioning useless, at least for the time being. Though the W3C specifications for style sheet positioning contain most of the tools needed for good design, Microsoft and Netscape have done a particularly poor job of implementing them, so that properties such as borders and margins display quite differently from browser to browser. If you are creating a site for a diverse audience you should steer clear of style sheet positioning for now and design your pages using layout tables as described below. If standards compliance is a priority, use style sheet positioning for page layout, but keep your layouts simple and be ready to accept variability across browsers and platforms.
Standards compliance should always be a priority, and these guys should know it.