Here's a Library of congress site that has shots from the depression era and WWII from the FSA and OWI. We've all probably seen some of the BW FSA shots - there are a lot of color shots as well. Some of the work goes way beyond the documentation intended by the programs because of the talent of the photographers.
http://memory.loc.gov/ammem/fsachtml/fsowhome.html
It's not the easiest site on which to view pics, but worth the effort I think. A lot of pics so I'm going back exploring once in a while I think.