Ask HN: Best to-to list, outliner, task manager

I'm seeking a simple to-to list, outliner, or task manager to help me list individual tasks -- and to sub-list in priority order the steps needed to accomplish each task.

I think a tool like this was posted here some time in the past, but I cannot remember its name.

If you have any suggestions for a tool that can handle this in a simple, effective interface please post it in this thread -- and let's discuss the pros and cons of each so I can figure out which is the best tool for my needs.

I seem to have a huge number of tasks to accomplish in the new responsibility I've taken on as a manager of a small farm property, and in between programming projects I would love to be able to go to a simple online tool and immediately see a complete list of all the tasks I need to accomplish -- along with the required steps needed to complete each task -- so I can focus on what I NEED to focus on and therefore become more productive.

Thanks.