If you're sick of hearing about GTD, relax, this isn't about that. This is about a program that's just a to-do list; no contexts, no realms of responsibility, no next actions to speak of. It's called Dejumble and it sits nicely in your menubar and allows for fast creation of new tasks with tagging and basic categorization. Tasks can have due dates and notes as well, without all of the extra goodies that a lot of people just don't need.
I was, however, frustrated by the keyboard/mouse switching necessary to add new tasks. I'd love for a hotkey to open the window, and to be able to just tab through the input. But it's still in beta (public), and development is under way. Integration with system apps like iCal and Mail is apparently on the way.
If you're sick of bloated task managers, this may be a good fit. Fair warning, though: every time you run it, it will add itself to your startup items without asking. And there's no easy way that I could find to quit beyond
killall Dejumble. There, you've been warned.