I've had the new design up and running for a while, and decided I'd actually check the XHTML validity... I am advertising the site is being 100% valid XHTML (right at the bottom of the page). Well, I was duly surprised... the only thing that isn't 100% compliant at this time is my calendar, but that's kind of understandable as it's not my code.
I am, however working on this. I've found a way to export my calendar in XML from our calendar server... all I need to do now is make it do something useful and have valid XHTML. Once I've got that all working, I'll let you know.
[EDIT: Had to change title cos % doesn't work very well in URL's.]