Great concept!
Just as important as the things you want to do, are the things you really shouldn't be doing - like your bad habits.
This would be a great way to keep track of all those little things, which when added together, can lead to you wasting time, being unhealthy, self-destructive/defeating...the list goes on.
And just be listing your 'not to do's', you're bringing them to your attention - which, I suppose, is the first step of the battle.
This is something I'll be looking at myself (and is kinda connected to an idea I've already had/been working on).
Great hunting :)
RE: Via Negativa - Not to do list