In the past week I've finally decided to go all CSS Zen Garden on my site and remove the last vestiges of layout information from the XHTML code, thus shifting it all presentation information to the stylesheet (the CSS file). For the most part, the site should look and act exactly the same as it did before. Minor non-CSS/XHTML changes include the movement of the About page to it's own section and the update of that page's content, and the re-tagging of news posts.
If you don't know what the CSS Zen Garden is, check out that link above. My take on it is that it's a site aimed to promote CSS-based page design and the separation of presentation info from the page code. This puts all of the design information of a page exclusively into CSS files, and with that you can let web designers go wild. Take a look at some of the 200+ user-submitted designs for the CSS Zen Garden. If you look closely (or just read what the page says), you'll see that the HTML code stays exactly the same from design to design; all that changes is the stylesheet file (and images) applied to the page. Pretty cool eh? What, no? Damn, I thought it was.
I'm not gonna go and start creating multiple stylesheets for my site, but I am aiming to make at least one, just to make sure that I did the whole thing properly. And if I like what I created, I'll make that stylesheet available as an option... somewhere.