If you are talking about a mind mapping app, there are many options. I have tried quite a few out.
Freemind is a great free and open source application. MindNode has a free version and a pro version for $20. Both are available in the app store. There is also
Xmind with a free version and a Pro version for $49 per year.
Inspiration is a great package that costs $69, but it does not support an OPML export that I find essential for porting the data across applications. It is targeted for the K12 market.
MindManager comes in at $249. It is very capable and has some interesting interactive exports.
NovaMind is another capable program that is about to release a version 5 that looks very promising, but development has been slow and release is over a year late. The platinum version includes a presentation mode and task management. There are 3 versions: Express $49, Pro $149, and Platinum for $249.
There are others that I have not tried such as MyThoughts (Looks interesting and priced at $49), ConceptDraw, and others.
