Edward Tufte is a hero of mine. I know that I will be soon seeing endless PowerPoint presentations being screened in the lecture rooms of the university. For what purpose, I wonder? That's why I'm with Edward on this. We aren't very good at this.
Tufte's book The Visual Display of Quantitative Information ought to be required reading for every graduate student. It contains what I am certain is the best graphic display of complex information I have ever seen--Minard's map of Napoleon's march on Moscow in 1812
Napoleon started with over 440,000 men on the left; at Moscow he had 100,000; and by the time he arrived back he had only 10,000. The map plots numbers, the course of the invasion, rivers, cities, temperature and time. (You can find out more here.) If Minard could produce such an elegant and fascinating visualization in 1869, we have to wonder why the kitten population isn't thriving instead of being decimated.
Every time I read a draft of a PhD dissertation I come across graphics that float alone on the page, disconnected from text, idea or analysis. What the hell are they doing? Very, very rarely are these things self-explanatory. My response is automatic: read Tufte and don't come back until you have. It sometimes works.
I think I have found a worthy accompanist to Tufte in the guise of David McCandless, a British journalist, turned data visualizer. McCandless believes passionately that information is beautiful if you present it in the right way. He spoke at TED this year. And I am going to show his talk to my research methods students. McCandless has a way of taking vast amounts of information from sources such as Facebook and military budgets and putting them into a visual context that makes immediate and intuitive sense.