Well, as is usually the case, my inner-nerd took over and told me that this webpage needed to validate as XHTML 1.0. I couldn't wait for the managers of the CMS I'm using to make the move from HTML 4.x to XHTML 1.0, so I went ahead and did it myself this morning. Surprisingly, it wasn't that tough. I used a progam called Tidy to do most of the converting. The only real problem is that as configurabe as Tidy is, I could find no way to tell it not to insert the main HTML tags (ie, html, body, !DOCTYPE, etc ). This was a problem because the website is dynamic and pages are built on-the-fly from smaller HTML files through PHP. When I went to convert all of these 'partial' HTML files to XHTML they would convert just fine BUT would have all those extraneous (in this case) tags, which I had to remove.
After all of that was done, I started testing the validity of the site. I ran into a few problems because, again, Tidy treats all HTML files as if they are the only file being used and not as if they are part of a template system. Most of the hang-ups were just a matter of figuring out what start tags went with what end tags in the final, PHP-produced HTML file. Nothing major. I also went ahead and made sure that my CSS was valid as well. You can check the XHTML validation here and the CSS validation here.