An easy pick for me but it captures the last decade so well. Lincoln looking at the noose/halo is what sends this one over from being just a funny picture into being genuine art. It should be in a gallery. It should be in the entryway to the White House.
At least for America, (and not in a funny way, I should add) is the pepperspraying at UC Davis. It really summed up how the following years would go.