Despite the coherent look and feel of my site, it is controlled by a ragtag collection of half a dozen different systems. I have several separate Movable Type weblogs site up, one for the main weblog, one for the projects, one for the 100. The photo galleries are generated by a homegrown script. The Safari CSS hacks pages are generated by another. The main Safari page is handcoded. There is no one CMS available that does everything I want to do on my site; I use a best-of-breed approach and glue the pieces together myself.
I recently redesigned my entire site. I don’t know if you saw the previous version, but it was very minimalist layout, with the big Orb O’ Zen on the side. No section-specific colored headers, no tabs. Search box at the very bottom of the page. About the only thing the designs had in common was the breadcrumbs along the top.
You know how many files I changed during my redesign? One: my CSS file. My markup didn’t change at all. I have 4000 pages of clean HTML markup, generated by half a dozen separate systems, and I didn’t have to touch a single one of them.
If you think tables are simpler, use them. Enjoy your redesign.