Drupal Tip #1: Node Privacy by Role defaults
Module: node_privacy_byrole.module
Drupal Version: 4.6.6
Many of my clients rely on some form of privacy to allow additional content to registered users, more often than not, to varying degrees. Normal drupal permissions helps out in cases where one could differentiate between content types for different permissions - more complex role divisions doesn't always allow that.
Node privacy by Role allows a lot more flexibility and I've been using it for months. The only reason I haven't been including it in every installation was the somewhat frustrating permission of setting permissions. It appeared to me that only the first admin user can set permissions, limiting other users to rely on defaults.
Much to my surprise, the module allows one to set permissions as well as defaults per node type from the content configuration pages (aka default workflow)
administer > content > configure (tab) > content types (sub-tab) > configure (for each content type)
*glee*
An application of this includes introducing a new user to drupal by including helpful howto's only visible to their various content providers.