I might be old-fashioned, but I'm still using a pen and notebook. I'm thinking of going digital, but all of the online to-do list applications are far too complicated — I don't care about categories, tags, or priorities. I'd just like to be able to type in a list of tasks for a given day and hit a box to mark them as done.
As a fan of Seven Habits of Highly Effective People, I have developed WeekPlan. It allows you to keep your whole week and your goals in perspective. (Thanks to http://teuxdeux.com for some of the UI inspiration)
The feature I find most powerful and yet almost invisible is the Overall Quadrant indicator. It tells you in which quadrant (cf. the book) you are spending most of the time this week by showing a different color. Your goal is to have it green, Quadrant II, important tasks but not urgent. Trying to get the green light has been very efficient to help me keep focused on what matters.
(I developed most of it in eight hours using a combination of asp.net MVC and jQuery and was really impressed by the productivity you get out of these two.)
While on-topic, just want to clear up misconceptions of org-mode. It is different from all the software/website task managers mentioned here. You can think of it as a meta-organization tool. A org software factory if you will. You can customize it to exactly how you want your thoughts, tasks, notes, etc organized.
This may sound like a lot of work, but there are a lot of sensible defaults, which is why most org-mode tutorials that scratch the surface make it seem like a sibling to other task management software. The base case the OP wants would simply be:
S-M-<RET>: create new TODO
C-c C-t D: mark TODO as DONE
If I may pilfer a quote, org-mode "outshines other [task management solutions] in approximately the same way the noonday sun does the stars." (Neal Stephenson on Emacs)
No pre-made org software has ever felt comfortable enough for me, so I roll my own.
I have a series of text files organized how I like. I added syntax highlighting in TextMate. I also wrote Ruby scripts that automate any parts that would be tedious if done manually. My calendar is just a glorified text file, specially formatted for ease-of-use.
I also wrote my own TextMate bundle that turns TextMate into a wiki, which is my exobrain.
Finally, whatever you end up doing, I would recommend doing something similar to my "jot" script. Basically, whenever I have an idea or come across something I want to address later, I hit F10, a dialog appears, I type my thought into the text box and hit enter, and then the message is saved in a file called jot.txt. At the end of the day I clean out my jot.txt. This allows me to capture ideas as they come to me without breaking my momentum of what I'm currently working on. You can find that script here: http://techiferous.com/2009/12/streamlining-your-workflow-wi...
Quite simple interface. Write your list, easy to manage times with the shortcuts (just go: ^ then type your due-by date, ie: tomorrow or friday and it'll set the date), and you can print it off if you still enjoy the nostalgia of pen and paper
Absolutely nothing works better for me, I've tried a lot of things from paper or post-its to writing my own software or using flat text files. I have paid for the pro version ($25 and can be accessed on an iPhone or Droid, web-only version is free) for two years now and I'd gladly pay $100 for it.
I haven't found anything better than a written list. There's something really tactile and satisfying about crossing items off it.
Every few days I rewrite the list onto the next page, drop things that are no longer relevant, expand items that are sticking around. The physical nature of the list, and the ritual of recopying it are really powerful, to me. Plus the fact that I recopy it frequently helps keep it from getting out of hand and naturally prioritizes it.
I say this, but I've been out of the habit lately. I need to start doing this again.
I have since added a few minor details, but largely it's the same. I still feel a bit bad for ripping off their design, but heck, it was just up my alley. But in all honesty, it sounds like http://teuxdeux.com/ out of the box would be just your thing. Personally I wanted to be able to have it stored "locally" where I had full control.
And to answer your question: I use what is outlined above and it works really well for me. The only drawback, perhaps, is that my "To do Some day" list has gotten pretty big. Everything I can't do right now but find interesting, or every little idea end up in that container. Not sure if that's entirely bad, though.
It's on the "Todo Some Day" list to make my version of it talk SyncML which would enable it to synchronize with existing mobile apps out there. I never considered porting the UI, but maybe that's an idea, it is really suitable for cellphones.
I've tried a number of different options - online and local files - but I've settled on Vim's taskpaper plugin (see link below) and a tasks.taskpaper file that I keep in sync across machines using version control. I don't actually even use Taskpaper itself, since I don't really want another application for this - just a file with a reasonable, and hackable syntax. (The syntax is simple enough that it's dead easy to whip up a script for any kind of display or search or munging you might want to do with your tasks file.)
I'm working on an app for this - Speckle (http://speckleapp.com). The main feature is that Speckle has multiple checkboxes per task, so if you're working in a team, or even just if some tasks take longer than others, you can check them off bit by bit.
I think you might want to look at http://www.toodledo.com/ - it is actually quite powerful (aka "complicated") but the amount of complexity is user configurable. So if you don't care for a certain category, you can just tell the system to ignore it.
The main advantage of something "online" is that it is easy to attach supplementary information to a to-do item - a file, a message-ID...
I use a hybrid of post-it notes, online calendar, paper notebook, toodledo, and e-mail. GTD it isn't - but it works.
[Edit - toodledo also allows you to assign tasks to other users. It is not quite implemented in the way I would like, but their deveoper is very user-friendly and they are always working on it, so I am optimistic.]
Nothing wrong with paper and pen but you need a system to make sure things don't fall through the cracks. I use and recommend the Franklin Planning system now Franklin Covey.
Gootodo (now called Goodtodo) is the best solution I've found. It's simple, without categories, tags or priorities (other than sorting by position). The differentiators for me are: calendar-based to-dos. I can create a to-do that I don't actually need to act on until next week, and it won't show up until then.
Also, awesome email integration, where I can forward an email to, for example, firstname.lastname@example.org, and the body of the email will be attached to a to-do that shows up on that date. This is a fantastic way to get in the habit of emptying your inbox as well. Things you have to do don't linger there, you just forward them to your to-do list.
Simple and elegant, and more than worth the $3/mo I pay for it.
Things on the desktop and the iPhone. If you buy into the GTD system, I'd recommend it. The iPhone app syncs via WiFi to the desktop app whenever you're connected to the same network (I'm hoping syncing via the 'cloud' is coming soon). Ubiquitous capture is what it's all about, and Things is good at it.
It also helps that the app is simple and well designed. I don't use the tagging or much of the scheduled tasks features. Otherwise, there isn't much that beats pen and paper.
I have a private repo on git-hub with minor things I am writing (i.e. not multi-week projects), priority registers (only allow myself 3 things on it), lists of things to read, list of things to do in spare time, list of ideas for future projects, and directories with notes on books and practice applications that I write when learning something new.
I like it because it's free, and I can even sync it with my iphone free - just have to pay $1.99 for the app
Nice clean interface, has a nice Google Chrome extensions, and for me it is intuitively how I order things - by date and importance. I just use "Project -> Task" to signify next actions within projects
Second the vote for OmniFocus. The key for me was synchronization between multiple computers and the iPhone. The iPhone app seems a bit like an afterthought (it's very slow to update, even when using their suggested tweaks), but synching between computers works great.
When I had jobs that required me to use Huge Enterprise Planner v 10.0, i copied my tasks as succinctly as possible to notepad. It's lightweight, doesn't get in the way, and just works. Todo.txt, and I keep it to 10 lines per day.