A common reason people give in opposing the construction of new Walmarts is that they supposedly lower housing prices nearby. This complaint is wrong. New research by Devin G. Pope of University of Chicago’ Booth School of Business and Brigham Young University economist Jaren C. Pope shows that for 159 new Walmarts opened between 2000 and 2006, they on average actually increase housing prices by between 2 and 3 percent for houses located within 0.5 miles of the store and by 1 to 2 percent for houses located between 0.5 and 1 mile.”
Their paper is available here (pdf file). Warning: lots of stats are used.