I use a variety of mind mapping tools. I use MindNode Pro on my MacBook and MindJet Mind Manager 8 on my PC. On both machines I use FreeMind and, for me, that free tool is the best of them all. What I have missed is the opportunity to do collaborative mind mapping with a clean and simple interface. X-Mind is available for Mac, PC and Linux and has free and paid ($49 USD p.a) versions. Click here to go to their website.