Hmmm, Taskwarrior looks interesting. I've been using DevTodo, but I find that more useful for software-project todos rather than general todo lists. I've also been using a personal wiki for organizing bigger projects because one can put one's notes and scribbles with it.

What I wish existed was task software that could double as a notes/outline/mind-mapping tool, and also be able to be updated by sending email... I guess I'll just have to work up a kluge that interacts with a wiki or something...