pageoneresults - 9:18 pm on Feb 7, 2007 (gmt 0)

If you put <b> into an html 4 or xhtml document, it will not validate.

Yes it will. :)

On the other hand, I used a popular theme with a CMS that is xhtml compliant and all the pages validated perfectly. It looked great on firefox, mozilla and opera. In IE it produced a page, that was incredibly difficult to read.

Doesn't sound like an HTML/XHTML Validation issue. More of a CSS issue?

Give me thoroughly tested over validated any day.

Validate first, test second. Eliminate one part of the equation. If testing fails, at least you'll know its not because of invalid code. ;)