As an economist I love graphs, perhaps too much sometimes. I had my mind blown yesterday! Hans Rosling has created a system to use UN data on basic economic indicators in the most visually stimulating graph I have ever seen. His graphs plot every country over the last 40 years, then the plots move over time to show change, the dots are sized by population and colored by region. Click on this graph to see the relationship between life expectancy and GDP per capita. If you have 20 minutes, I highly recommend his TED talk too.
Thanks to Dani Rodrick for pointing out this work on his blog.