I've watched a bunch of documentaries about the corporatization of contemporary society, the transformations of our food systems, and unfair labor practices around the world.  They are all similar in tone and production values, and I view them with the understanding that the filmmakers have a very strong agenda they just need to get out there.  I watched one recently, though, that stands out as more nuanced and thought-provoking than most: Wal-Mart: The High Cost of Low Price.  I went into it thinking I would see a film about sweatshops and the squashing of local businesses, but it also hits hard on discrimination in the workplace, substandard health insurance for the lowest wage-earners in America, anti-unionization efforts, and the failure to provide for the safety of customers.  In light of my other recent recommendation, James Howard Kunstler's Long Emergency, the movie's evidence is particularly poignant.  

...the destruction [corporations] wreaked was as manifest in the ravaged towns of Ohio and upstate New York as in the environmental degradation of China...In effect, the American heartland was overtaken by a new kind of corporate colonialism, emanating from our own culture, but no less destructive than the imposition of foreign rule.
    Americans failed to recognize the essential fraudulence of the idea that this destruction was 'creative' and would lead to a higher good--in other words, the end justified the means, even as they watched their towns die around them.  Corporations such as Wal-Mart and its imitators used their wealth and muscle to set up 'superstores' on the cheap land frontier outside small towns and put every other retail merchant out of business, often destroying most of the town's middle class.  They also, incidentally, destroyed the local capacity to produce goods.  And the American public went along with it for the greater good of paying a few dollars less for a hair dryer. (The Long Emergency, 189)  

Check them both out ASAP - I got the movie on Netflix.  I've been to Wal-Mart twice in my life and will avoid it at all costs in the future.  I don't live in a place where Wal-Mart is an option; in most places, it is the only option for certain basic needs - for that and for your community, I am very, very sorry.