To ideally build a content management system you would want the following extensions:
Data Assist
Security Assist
Framework Builder (not essential, but a very useful extension)
CSS Form Builder (for the email functionality)
Form Toolkit
Possibly Dynamic Web Charts if you are recording stats (i.e. page views)
I've just spent 3 months developing quite a complex CMS with page versioning, anayltics, feeds, navigation management and a few other bits and bobs. The WA tools can help to make the process quite a joy!
Cheers