This, ladies and germs, is my current task management system, a legal pad and colored sharpies.
Assumptions behind this: 1) Todo lists are DISPOSABLE, they have almost zero value after being completed (why are you saving them in a high quality book like a moleskine?) and 2) Todo lists should be VISIBLE and easy to use.
I can get away with a simple system like this because I have so few contexts. I generally don't track tasks and projects for my personal life or anywhere but at work.