Why should I database drive my website?

We came across an interesting customer this morning who had more than 1000 pages of static html.  As we started talking we found that this was over the timespan of 10 years that this had grown.  That obviously breaks down to 100 pages, which depending on your organization may sound like a lot or a little. Well with the same math, that breaks down to 2 pages (1.9 technically) a week.  As we work to build a migration strategy to convert these pages, it’s something to consider when planning out your own website.  How fast will it grow?  How often will I be updating its content? And depending on how you build it, how often will I be re-skinning (redesigning) the site?