Transitional and Strict DOCTYPEs

Every now and then, I write some HTML with some CSS thrown in. I'd insert the ol' XHTML DOCTYPE directive, but I'd never bothered validating my code (aaaarrghhh you sinner!!), nor finding out about the differences between Transitional and Strict DOCTYPEs. Well, I just found out today when I came across this article, extolling why we should go Strict (and CSS).