The smart people over to Informationisbeautiful.net created something called a The Billion Dollar-o-Gram . Its a Treemap. I don’t visually get why its called that, but it’s the method for displaying heirarchical data by using nested rectangles.
What I like about it is the relationships. Understanding proportions when talking about big numbers is difficult, so an illustration like the one below helps immensely, especially when people mention a few billion spent on this or a few billion going on that.
I suggest checking out a book by them as well. It’s called The Visual Miscellaneum and it’s $17.81 over at Amazon.com .
One more item about their work, they provide a link to all their supporting data .
Working Thoughts 