OrgMode

Your life in plain text. That may sound weird, but definitively this one is a tool that you have to try if you like personal management and all thing GTDish.

This tool not only helps you to be more productive but also to keep you information at hand. It has project management features that will help you to organize your life and professionals goals into ordered groups.

The basic unit of information is a headline, and from this all the software expands. A headline can have several subheadings, text associated and specific keyword. For example if it is a task, a TODO keyword will precede the headline. It also supports tags, properties, clocking time and a powerful publishing framework (to export your files into formats like PDF, HTML for easy displaying). It includes an agenda for appointments and day-planning.

All of this is highly flexible and configurable, making perfect to adapt it to personal preferences.

The fact that it runs on the top of Emacs (a powerful Editor) can be scary, but learning a little bit of Emacs to dive into Org Mode worth it. Totally recommended.

in reference to: Org-Mode: Your Life in Plain Text (view on Google Sidewiki)