Bottom line (and I agree)–lead with the data, but unobtrusively–don’t overtax the reader. The first thing you see is an intuitively simple breakdown of income distribution. The use of color is excellent–you don’t even have to read the legend closely to understand that dark means highest concentration of income (rich) and light means least (poor). And you can see at a glance how this plays out across states.
However, I did spend a minute trying to figure out what the top horizontal line meant on the second part of this chart (income distribution by state) and realized, belatedly, that it was the national average. I would have treated that just like a state so that users could compare easily, perhaps setting the color differently (e.g., dark blue to light blue). And, as Junk Charts correctly points out, ordering the states by something other than alpha order (e.g., quintiles) makes sense.
There’s some interesting back and forth about how the top and bottom scales are colored. Same colors used for two different scales–good or bad? Design or accuracy? You don’t always have to choose one or the other–I would have opted for a different, albeit complimentary, color scheme for each of the two.
Here’s the original infographic on income distribution, posted back in December 2011.