The Journey to Todoist
Before computers they were paper, of course. I went through all manner of notebooks in my search for something ever better. I even used a folded piece of paper that would fit in my shirt pocket; moving from quadrant to quadrant until I had to start a new sheet by copying the uncompleted tasks forward. Lightweight and convenient.
For everyone who just can't let go of paper, and I sympathize, here is a tip that can make paper more viable. You use the paper edges as an index. See this article in Lifehacker that explains it pretty well...