Knowledge workers output is information and we need to have the right tools to get the job done. I have been using two great products for years, Mindjet's Mind Manger Pro 6.0 and FreeMind 0.9 both have been useful in different situations. Mind Manger is just plain easy to use with Microsoft Office 2003/2007. FreeMind is great because it is free and Java-based so it runs on just about any operating system. Check out Life Hacker's article on Hive Five Best Mind Mapping Software is a must read for anyone who does a lot brain storming with their teams or clients. What do you use for brain storming tools?