A thousand words
While in Washington, DC for the 2010 APSA meeting, I gave an invited talk at the Optical Technology Division of the National Institute of Standards and Technology, on techniques for visualizing data with large numbers of observations in multiple dimensions. My thesis, in essence, is that the value of a graphic is a function of the degree to which it is necessary and and clearly conveys information in an efficient manner. The slides, which consist primarily of visual examples, can be seen below.
Incidentally, the arc diagram of connections between Congressional Twitter users was featured in Miller-McCune magazine.