Representation of knowledge

I recently was surfing blogs and wandered into wikipedia's concept map and mind maps.

I already tried mind mapping technique before. I agree that this type of knowledge/ideas representation is much more creative and natural than all these lists and tables.

But concept maps become an invention for me. Now I see that concept maps are great way to represent knowledge, thoughts and.. concepts! They also help to organize your ideas and advance them.

I evaluate CmapTools for creating concept maps. It is easy to learn, and it is free!
Mind Manager is good for mind mapping. But it is still commercial :-(