Unfortunately, in that fast-moving thread, and with Detritus having posted only a bare link (no additional comment), many people might have breezed on past. If you haven't read that Wonkblog post, you really should do so.
I think some of the graphs there are important enough that they're worth re-posting here. I'll also add a couple of others that I created myself.
Graph 1: The US has far more deadly crime than other developed countries. In the US, rates of deadly assaults peaked a generation ago, and have been declining rapidly. In many other developed countries, rates have also been declining, though this is harder to see because their rates of deadly assault are so much lower than ours.
Graph 2: Within the US, the South is by far the most violent region, while the Northeast is the safest.
Graph 3: Gun ownership rates in the US are also declining over time.
Graph 4: When it comes to homicide by firearm, the US is an extreme outlier among wealthy nations. (Yes, I made this figure myself. Data sources are here and here).
Graph 5: Another way of visualizing firearm homicide rates in western countries.