I'm beginning to become a big fan of the tree map. It is very useful to see where business is coming from. One of the cool features in Tableau is the user can bring dates to a row and then the tree maps also act as a bar chart comparing where the business is coming from YOY.
Sample Tree Map from Tableau
As you can see above I can tell 2007 was my best total sales year with declining sales throughout the years. The decline was primarily driven by Office Machines as the size of that box never returned to its largest total in 2007.
I can see myself using this for many different dashboards and analysis in the future. Maybe I may even use bubbles.