xmind should fit your needs.
- Windows Application
- Exports to Excel/Powerpoint (in paid version)
- Very simple, very efficient to use with a group in a room (after a easy, quick learning curve)
- Can be used to task and track tasking (not as robust as say outlook or a true work tracking application
You can drill down into any of the non-core items (in this picture EID) and make them the center of the plan to help focus work on one item. Files can be directly attached to any of the subordinate items and markers (like check marks, questions marks (right side of screen shot) can be added to each item)
This is just one chart type, the program provides fishbone, mindmapping, matrix and brainstorming features, provides tasking and dates complete with Gantt views. Compatible with office and PDF.
The tool has a free to use version and a paid version, the full paid version is still only 99 USD, worth trying since it costs nothing play.