I looked at several and keep going back to... Handwritten sticky notes. Pasted on a wall, easy to move around and see my thoughts. I'm not anal enough to color code them, but the woman who showed me how she does it color codes everything.
I kind of go old school on a lot of this though, and come from an era when story boarding was how you put together a movie. I have to admit, I rarely mind map any more, I just set up an outline in Word and move it or change it as needed, adding notes where I think of them and working from there. Started when I seriously started doing non-fiction where everything is sold from an outline and written only under contract.
I did like Freemind, but it always had issues with Java.
Jeff