If I can suggest anything, don't use Frontpage - it generates a lot of messy code which can generate problems with modern browsers. I think that CMS is much better - once prepared can work almost without servicing.
PostNuke is quite old and I'm not sure how large (and how active) community support it.
Mambo 4.5.1a is my "weapon of choice". It's simple, small, very very flexible and configurable, has large and very active community and has a lot of add-ons and extensions. Check
http://www.mamboportal.com
HTH