Jeffrey Heer, Michael Bostock, and Vadim Ogievetsky provide a good overview of some of the more advanced data visualization techniques in ACM Queue:
This article provides a brief tour through the “visualization zoo,” showcasing techniques for visualizing and interacting with diverse data sets. In many situations, simple data graphics will not only suffice, they may also be preferable. Here we focus on a few of the more sophisticated and unusual techniques that deal with complex data sets. After all, you don’t go to the zoo to see Chihuahuas and raccoons; you go to admire the majestic polar bear, the graceful zebra, and the terrifying Sumatran tiger.
You’ve probably seen many of the techniques they present, such as stacked graphs, small multiples, and arc diagrams, but at the very least you’ll get the names and some brief descriptions of what you’re looking at, so you don’t have to call it the circly-thing-with-curvy-lines graph again.
Plus most of the examples were made with Protovis, an open-source toolkit for visualization, and you can grab the code to help you with your own visualization project.