If you're looking for one of the most comprehensive brainstorming applications possible on the Mac or are looking for a replacement for OneNote on Windows, then you may find Curio a very interesting option.
Curio's features a free form interface and tool kit that allow you to place items anywhere you want including notes, pictures, audio and even video. The only limits are your imagination as you can place elements in any position which gives it a distinct advantage over all those similar programs that restrict you to text boxes or certain areas.
You can even give your brainstorm plans or notes their own unique look thanks to a variety of backgrounds and styles such as note paper, graph paper style and linen paper texture for example. However, Curio is a victim of its own depth in a way. Unlike similar programs, Curio isn't particularly easy to get to grips with due to the sheer number of features it offers but a very detailed user guide is available for those willing to make the effort. Those that like to record their ideas on the move and don't want to carry their MacBook around with them too much may also be disappointed to hear that there is no iPad version of Curio yet either.
As far as mind mapping and brainstorming applications go on the Mac, Curio is one of the most complete out there..
