Q-Q plots aren’t always the easiest plots for people to grasp (at least initially), but once they’ve gotten the hang of it Q-Q’s are one of the best ways to display p-values and the like. I was recently putting together a couple of slides about some results, and I needed a good introduction to point geneticists to. The best intro by far I could find was from UMich, which offers a great walk-through:

http://genome.sph.umich.edu/wiki/Bar_Harbor_Statistical_Genetics_Workshop