Version 2.2 of the To-Do List Plugin is out.
New in this version are the option to sort by assigned user and the Master list feature.
The Master list can be selected on the settings page under List View. This feature allows you to have one main list that individual users cannot edit, but they can check or uncheck items on it. Changes to the main list affect all users. You only want to give regular users the ability to View and Complete posts, otherwise they will be able to edit the main list.