Hey Elaine,
That method definitely does help me with self-determination. After doing that for a while, I got into the habit of tricking my brain by saying "I'm only going to work for 15 minutes"... and then, seeing what kind of results I'm able to achieve by doing that, it helps my determination a great deal. You can achieve best results by reaching a state called "the flow", where you are so consumed by what you do, you don't notice anything else going on around you. You can read more about it here:
http://en.wikipedia.org/wiki/Flow_%28psychology%29
If I can just chip in with advice on Todo lists: I experimented a lot with different ways to keep them, and I found the best and the easiest solution is to use Back pack from 37 signals:
http://www.backpackit.com/. It's free (they do have a premium version that has more features, but I haven't felt a need to use it yet), easy to use and solves a major headache for me, which was how to be able to update my lists at home and at work.