On a recent roadtrip, eatstoomuchjam, alisgray, and I stopped at an abandoned mall in Illinois. While the town itself was a pretty fine example of urban decay, the mall was more than we could have hoped for. Here are two examples of the mall taken from our approach in the parking lot. The rest of the photos I snapped can be found here.
(ETMJ may post some of his own pictures after he gets them developed... These were just digicam shots I snapped while wandering around.)