Pro's and Con's - CSS Layouts

I've recently held a discussion on the pro's and con's of using CSS almost totally to organize and manipulate web layouts. You see, I built a practice layout using as little html as possible and having it driven by as much CSS as possible to see what I accomplish. But as usual, I had complications (in which I eventually got around) in firefox, such as padding issues.

Anyway, I figured I would create this topic to get some pointers as to what you all would say are pro's and con's (con's probably being the more important to know for sure what weaknesses these kinds of layouts will have) are of using majorily CSS-driven websites.