imindmap
I always found iMindmap to be by far the best mindmap program. Its a bit costly for home use but not by business software standards, and is Tony Buzan's own product.
It does all the usual stuff a mindmap program does, but the maps it produces are so clear and visually appealing that you're attracted to using it - it really is a pleasure to make maps on it. the other advantage is that its skewed more towards the creative side of thinking that other map programs, which tend to be very modular. Its easy to add images, branches of different thicknesses, unusual colour variations, clouds, and all that good stuff. Since most office workers tend to be more focussed on the logic/order/prioritising way of thinking on a day to day basis, it helps open up the creative side of thought a bit more.
I normally do a map by hand but if its going to be shared, or its one thats going to be around for a long time as the basis of a project, I either do or redo it in this.
Example
http://www.imindmap.com/articles/files/correctFormula.jpg
http://www.imindmap.com/articles/files/ProblemSolving.jpg
The trial is free so see if it floats your boat.
