city government

Looking for any advice from any large city government drupal site admins that have figured out a good way to set user permissions in a way that is most effective. Do you have a smaller, nimble group of power users who update content and are good writers, but a much larger group of contributors who can write and submit but can't approve? Trying to figure this out as we move our city site to Drupal over the next year or so. thx.

Scott