If you’re on a Mac and looking for an easy and stylish to-do list software you might want to consider Things. It has a slick interface, allows you to keep items organized for different contexts (home, work, etc) and best of all (for me at least) you can very easily add tasks to it in one simple step using a keyboard shortcut (Ctrl+Space in my case).
With a version for the iPhone that syncs as well, this might be the productivity tool you’ve been looking for years now since you first read that wonderful (but hard to put into practice) book “Getting Things Done” by David Allen. The cons will probably be the price and it being a desktop app but maybe you can live it that?
I’ve been using it for over a month now and so far I’ve been happy with it. To be honest it hasn’t boost my productivity. These things are like buying news shoes for running: the shoes won’t do the running for you!