I've recently found TreeSheets when I was looking for some good note
organizer program. I am more the spatial type of guy, I love mindmaps
(and used Freemind for that), but they can be cumbersome if your
documents start to grow. TreeSheets is basically a mixture of mindmaps
and traditional editors, it takes a while to get used to it, but you
won't regret it ;) For me most important: it is fast and it doesn't
get in your way (you can do everything with your keyboard).
From the website:
Suitable for any kind of data organization, such as Todo lists,
calendars, project management, brainstorming, organizing ideas,
planning, requirements gathering, presentation of information, etc.
It's like a spreadsheet, immediately familiar, but much more suitable
for complex data because it's hierarchical.
It's like a mind mapper, but more organized and compact.
It's like an outliner, but in more than one dimension.
It's like a text editor, but with structure.
Free, available for Linux/Windows (and there's a alpha Mac-Version):
Check the tutorial to get an impression: http://treesheets.com/docs/tutorial.html