Inspired by Brian's theme for the month, this basin and range landscape in central Idaho caught my eye. I love the way the center-pivot irrigation boundaries outline the edges of the alluvial fans. Closer examination reveals even more juxtaposition, as a river cuts through the middle of the valley, further limiting the extent of agricultural and human influence. I'd imagine that the arable areas have been somewhat dynamic of historical time as the river changes course and as the fans continue to build. In the second image, you can see some incomplete irrigated circles, where presumably the alluvial fan is too active to allow agricultural productivity.
The flash earth imagery is also rather nice. http://www.flashearth.com/?lat=44.553052&lon=-113.819471&z=11.9&r=319&src=msa