Xmind - Xmind is a brainstorming and mind mapping application.
bubbl.us - Bubbl. us is an easy-to-use, online brainstorming software. With Bubbl. us you can create colorful mind maps and share them with others. Click here to view examples of mind maps that were created using Bubbl.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Kinopio - Thinking canvas for mind mapping, brainstorming, and moodboards
MindManager - With MindManager, flexible mind maps promote freeform thinking and quick organization of ideas, so creativity and productivity can live in harmony.
dotstorming - A space for real-time brainstorming and decision making