Quick thoughts: CMS Pros: + Templates. You can easy change layout and design (or adsense code). You do not need to find and replace tons of html pages. + Comments, raters, other dynamic things. + Auto RSS generation. + User management if you need a multiuser site. + Access rights by users. CMS Cons: - Vulnerabilities. Popular CMS are attacked by hackers. You need additional efforts to make an security fixes and so on. I think static html may be good for several-page-websites, not more. It is difficult to maintain and change it on the larger site.
Adobe Contribute is another option. It basically allows users to browse to a page and edit much like you would in Word. It's essentially Dreamweaver in WYSIWYG mode so you can edit content within a template and use FTP and/or an approval process to upload changes. A web developer can create the templates and anyone with web browser and Word skills can update and I believe your security is better than many of the free CMS systems since you don't have admin access to the site only FTP.
CMS might have performance issues, but today these are all negligible unless you get slash dotted. Static html is very easy to get started. That's what I use but I'm going to learn some CMS too.
If your site is database driven and has lots of pages (100's or even 1000's), a CMS is the way to go. It allows you to maintain the site a whole lot easier than having to manually edit every page on your site.