Eventually, I decided to scratch this itch with my first web-based app, Pocket. I released an MVP a few days ago and it gained quite a bit of traction here on HN, receiving thousands of hits and nothing but positive feedback. While building Pocket, I translated much of my experiences with physical note-taking to make the app feel as natural as possible, and I'm really pleased with what I have accomplished thus far. Over the past month or so, I've recorded hundreds of thoughts - everything from new Pocket features to songs I want to download to little miscellaneous reminders, etc. If you're interested, check it out at http://letspocket.com. I'd love to hear what you think and whether or not it suits your needs.
It may help to think of the number one goal of a todo list as a place to get onto paper (or bytes, whatever) all the things you have in your head that you think you need to do, NOT as something which will help you get more done. The primary benefit is to remove your anxiety about having to remember everything you need to do. Once it's all out of your head and in one place, you can easily determine what it is you need to be doing right now, and forget everything else.
Complicated GTD or todo systems just bog you down and take too much fiddling and constant review/maintenance. I use two lists: a "dump" list where I put anything/everything that I need/want to do, and an "action" list where I move a few things from the dump that I'm going to focus on for the day or very immediate future. It's a simple matter to go through the dump and pick out the highest priorities and move them to action.
If you're struggling, I'd advocate trying something simple like this and forgetting more complicated systems. Google Tasks is perfect for something like this.
That's what worked for me and that's why I love Workflowy, I can set the to-do on my way and rearrange the best way at anytime.
The right system is totally secondary. It can be as simple as a note in your front pocket. In fact, a written note is good because you have to continually rewrite it, and that makes the tasks stick in your head. It also becomes a huge hassle to keep writing down the same things instead of getting them off the list. When I have to kill my list I do this.
Day to day I use google tasks (iphone-dock and firefox-sidebar) and it stays in my face all day between those two.
A long list is good. There's nothing that guarantees failure in todo world like having tasks like: "Profit". You have to break everything down to the smallest particle you can, then you knock off more things more often and you get used to using your system.
Determination is the most valuable skill in the world, stick with whatever you do and it will pay off in every aspect of your life.
During the final's week, I added in to-do things like what I would be studying and when in order to prepare for all of those exams: http://peri.me/albums/aDemoUzer/1/original/FIanl%20week-F10....