WorkFlowy

WorkFlowy is a good tool for task listing and outlining. It mimics the natural thinking and provides a single place to manage all the tasks and chores. WorkFlowy is an organizational tool that makes life easier. It can help organize personal to-dos, collaborate on large team projects, take notes, write research papers, keep a journal, plan an event or a celebration, and much more.

Here's what Matt Cutts, Head of Webspam at Google has to say about Workflowy- "WorkFlowy has become one of three tabs that I keep open in my browser, along with Gmail and Google Calendar."

I am thoroughly enjoy using it, you'd too, perhaps. Check it out at https://workflowy.com/