Look at HTML::Mason before choosing a solutions. You might find it helpful. I have achieved staggering success using it for large scale, highly interactive web sites.
It follows a component model, it allows filtering of pages, it can automate headers, footers, navbars, etc.
It plays well with CSS. My sites are completely style-sheet driven. And since the pages are made of of simpler, generic components,; at the page level I almost never have to worry about styles (or headers, or menus, or event behavior).
It plays well with mod_perl and Apache::Session, making maintaining state a breeze.
It may not be the answer for you, but you should check it out before making a decision.
You can see it at MasonHQ.

-pete
Entropy is not what is used to be.