Frictionless 2.0d1 - To-do list manager. (Free): "
Frictionless is a to-do list manager in the Getting Things Done style of David Allen. Specifically, it allows you to view your items in both heirarchical form, so that you're encouraged to document 'the next action' for all your tasks, and it lets you then slice by the Context needed to do them.
The idea is that when you are processing, you can use the projects view to capture all the things you have to do. Then when you are doing, you can use the contexts view so you only have to see the items you can work on right now.
This bypasses the problem with most to-do list programs in that if you do a complete to-do list, you have 200 items, of which only 20 are presently actionable. By slicing your actions by context, you only need look at Errands when you are ready to run errands.
Hint: In Frictionless a 'Project' is any task with sub-tasks.