I love making lists, but have a difficult time choosing the One True List-Making Solution.
I call this difficulty "restlistness", and I have it all over the place.
This is TaskPaper, my current favorite. Pictured are some of my assignments for one of my classes this term. The main reason why I like TaskPaper is because it is "just about fiddle-proof," to quote Merlin Mann.
TaskPaper behaves like paper and pen, but has some neat built-in features like filtering by tag. To see things that are due today, I can scan my list for the color my theme sets for items with the "@today" tag, or I can just click on a "@today" tag to filter everything else out.
TaskPaper doesn't nag me with notifications or integrate with iCal, although there are certainly AppleScripts that can add that functionality. So far, it is working very well because of everything it doesn't do. I am easily distracted by elaborate to-do list setups; this, on the other hand, was up and running within a few minutes on my Mac and synching with the iOS app as well.
Best of all, I've been getting things done.