I love graphical methods, and think that biostatisticians ought to use them more (in many sectors of my industry, they are using graphical methods more and are advancing the field). However, there are times when graphics deceive us even if they are done correctly, such as when one is trying to compare two overlaid time series.
Junk charts shows a recent example from the NYT. I think this example also shows that creating truly illuminating graphics is both an art and a science.
