I subscribe to that. With a notebook and a ball-pen, you beat every Palm or whatever.
A friend of mine switched to one of these “manager tamagotchis” about two years ago, mostly because they were introduced by the company he works for. Interconnectivity, automatic search for conference dates (
if you think about that in depth: the devil must have invented that, or at least a saboteur), all that bla-blah. He was very happy with his toy… for several weeks. Today he would return to the paper-based timer he used before at any time, but his company insists on the electronic gadget. So, the only truly reliable organization tool in his life is the kitchen calendar his wife maintains… 
The idea of using a computer to organize oneself is seductive and compelling at first glance, and years ago, I tried this route several times. But every time I arrived at the same conclusion: Nothing beats paper, as far as self-organization is concerned. (It may be otherwise if organization of huge projects with a lot of people is concerned.)
Why? First, because the time between a thought coming up (“I have to call Maria/buy milk/whatever”) and the moment it is conserved for further use is by far shorter if all you have to do is to open up a notebook , grab a pen and jot it down in an appropriate list, compared to get access to a computer, call up a piece of software, click here and there and start to type. Factor four, at least.
Second, because writing something on paper is not the same as typing something into an input field. On could think a lot about the psychology involved here, but I guess it boils down to: For most people, something handwritten is a stronger committment. Thus the magic of the signature. What you write on paper lasts. What you write into a computer can be deleted any time and traceless. And committment is important if you want to get things done.
Third, because the great advantage a computer provides in, let’s say, writing a text - that you don’t have to write it again and again every time something changes -, is in fact rather a disadvantage if to-do-lists are concerned. Yes, an item you enter into a databased system can effortless appear in a lot of reports, lists, popup windows, whatever - but does this help to get it done? That is, to get it off that databased system? In my experience it helps a lot more if I have to write this damned task “prepare tax forms” again and again on new lists to nourish my decisiveness to get rid of it ASAP and despite all uncomfort.
Fourth: Thou shalt not maintain more than one calendar. To use more than one calendar/time system/filofax/Palm/whatever will create more trouble in your life that using none, because you will spend endless time with keeping them all in sync (and you will endlessly worry about whether they are in sync). 15 years ago this was a killing argument for computerbased self organization, because you could not carry your computer with younterall the time. Today you can, but in addition to arguments 1-3, I would worry about dropping it accidentially. I use dedicated, leather-bound calendar/ringbooks since 23 years, and as I counted, I dropped these at least one time per year in a way that would have killed a electronic device. (It leaves it’s marks on the leather as well.)
I downloaded iGTD out of curiosity. Awesome application. This guy really has it.
But after some playing around I let it down, opened my notebook and striked out “have a look on this iGTD thing” on the list… 