My most effective and sustainable todo system has, so far, been a notebook with a new page for each day. On the evening the previous day (ideally... sometimes on the morning of the current day) I look at the previous day's tasks and copy the uncompleted ones onto a new page, then add to that page as I go along.
This forces me to review and eliminate tasks that I blatantly won't do (self-cleaning) and keeps track of other relevant tasks (no lost tasks). Works great.
When overworked, as another layer, I add a number next to the tasks, 1, 2, 3 or 4. This allows me to more easily ignore the 3's and 4's until the 1's and 2's are completed.
I was going to say the same thing. I tried org-mode (I'm a heavy Emacs user) and it didn't stick, I think the simplicity is what makes this doable. Also I have a nice history of tasks and it isn't tied to my computer or mobile device. I don't have to worry about syncing or backup or files piling up never to be read again or any of that garbage.
If you have tasks for managing your todo list on your todo list then it is too complicated.
I've tried GTD but no one tool works for me and I end up falling off of the wagon. Email is usually my downfall. I'd prefer everything on paper, whether Moleskine notebooks, index cards, or just folded printer paper. But taking an incoming email (that will take more than 2 minutes to act on) to a task on paper is usually such a heavyweight process that I never do it.
So I end up trying to manage everything in my email+tasks systems (Exchange/Outlook for work and Gmail for personal). That works somewhat well, but breaks down for a couple cases. I still prefer a paper list where I can scribble new input as well, for meetings and offline / distraction-free planning time. It's not as hard to copy from paper to email+tasks, but I never seem to get it done.
Another vote for a notepad + copying. It's the only system I've ever stuck to, and the only thing missing from it (very occasionally) is not having my list online.
This forces me to review and eliminate tasks that I blatantly won't do (self-cleaning) and keeps track of other relevant tasks (no lost tasks). Works great.
When overworked, as another layer, I add a number next to the tasks, 1, 2, 3 or 4. This allows me to more easily ignore the 3's and 4's until the 1's and 2's are completed.