I say dynamic all the way. The advantages of dynamic website systems are so dramatic that my company stopped making static-page sites an option a couple years ago and now we exclusively develop content management system (CMS) based sites.
We also wrote a blog article about the advantages of a CMS-based site about a year ago:
Nine reasons your church website should be a CMS
The article was written specifically about church sites because that's a large part of what we do, but he principles are applicable to most types of sites.