I agree with @Bastien_Siebman, creating Reports with the Advanced Search is probably the easiest way to achieve what you’re looking for!
I would also recommend taking a look at these other threads where we discussed similar questions:
- Seeing Tasks with no Due Date
- How to search for active tasks with no one assigned? - #3 by Marie
- Is there a way to look at all overdue tasks from the most recent to the latest not including tasks due today?
Hope this helps!