The power of the ubiquitous web
XMind
This is the MM application I found more in sync with my needs. It has what it takes for a heavy demanding user yet is simple and very user friendly. I don’t like to use mouse very much, just the strict necessary. So specially when I need to catch up something real quickly I want a good keyboard oriented interface, it is faster going with tabs and enters than being clicks away from what I want.
There is a professional version of XMind which expands on the functionality of the base application and allows you to create online charts and collaborate with others. XMind Pro is $49 per year, but most people will find the free version more than robust enough for their mind mapping needs.
Features:
- Open Source
- The interface is simple and intuitive to use (based on Eclipse platform)
- Exports to different formats
- Useful templates for: Brainstorming, Meetings, Org Charts, Project Managing, Reading Journals, Personal Management and many more if you go with the Pro version.

References:
- Hive Five: Five Best Mind Mapping Applications: http://lifehacker.com/5188833/hive-five-five-best-mind-mapping-applications
- XMind: http://www.xmind.net/