If you frequently use mind maps in your office, classroom, or as part of your personal brainstorming and organization workflow, Blumind is a powerful and free mind mapping tool.
Many mind mapping tools have so many features and industry/profession specific sub-tools it takes forever to get them down pat well enough to use them quickly. Blumind is a dead simple but powerful application you can be zipping around after a very short and gentle learning curve. It supports multiple chart layouts (organization charts, tree diagrams, logic diagrams, and more), you can export to multiple formats (including JPG, PNG, SVG, and TXT), and is rich with keyboard shortcuts so you can rapidly create and edit your charts without leaving the keyboard and interrupting your flow.
On a personal note, I’ve been using Bluemind in the classroom for years now and have been nothing but pleased with it. It’s a perfect fit for a user who wants a super fast mind mapping tool without the overhead of learning a bunch of obscure techniques or counter-intuitive shortcuts.
Blumind is free, portable, and Windows only.