R Graphics, by Paul Murrell
A Visual Guide to Stata Graphics, by Michael Mitchell
Visualizing Data, by William Cleveland
Let's Practice What We Preach: Turning Tables into Graphs, by Andrew Gelman, Cristian Pasarica, and Rahul Dodhia
On the Effective Communication of the Results of Empirical Studies, Part 1, by Lee Epstein, Andrew Martin and Matthew Schneider
On the Effective Communication of the Results of Empirical Studies, Part 2, by Lee Epstein, Andrew Martin and Christina Boyd