I still prefer quality over always low prices. But still, these make my head spin a little:
FC: Will Walmart's "Sustainability Index" Actually Work?
and 11 Ways That Walmart Is Changing Retail -- for Good
TheAtlantic: The Great Grocery Smackdown
Update - how could I forget the story of Snapper lawn mowers and WalMart. From 2006, see The Man Who Said No to Wal-Mart Stories like this are why the superstore cannot be redeemed anytime soon.