Was hoping I'd find someone recommending Workflowy.
It currently does everything except calendar dates/notifications, which I'm currently working on adding to my User Script. (Shameless plug: http://workflowier.com/)
Workflowy is incredible.
It was the foundation for a system that saw me through a very productive time in my life.
I couldn't keep up with the complexity I layered in to it, so I'm building a webapp to do the mind mapping and translations to a to-do 'now' list. My biggest need was a dumping ground for all the things I knew I should be doing.
They took Workflowy and extended it (really started fresh, but that seems to be the idea)