I know this is on the to-do list, but since it's important to me, I thought I would place it here as well.
It might be good to have at least five roles with the following permissions:
Editor: edit any article
Author: edit only articles they write
Member: view all articles
Visitor: view only home page
It would be best if the role permissions could be user configured. Some might want visitors to be able to view all articles, for example.