http://www.time.com/time/magazine/article/0,9171,1226139,00.html
This is yet another article on the decision to pass a big box ordinance. This is from Time magazine, discussing the decisions of some big box stores to stay out of Chicago after their city council passed the ordinance.
This article restates what previous ones have brought up--that big box stores are making a big deal now, but will eventually have to compromise. Their desire to build in Chicago will outweigh the wage battles, especially economically speaking. The untapped spending in Chicago's many up-and-coming neighborhoods will be enough to outweigh the cost of a few extra dollars.
The article talked to Sante Fe's mayor, David Coss, who said that the city has only seen strong growth since its wage increase. He mentions that this growth has been seen in big box stores, but says nothing about small businesses.

The CFO of CostCo makes the statement that paying their workers $10 does not make them any less competitive. This raises a sticking point, though--CostCo already has a competitive edge by offering unique products with their model of bulk-buying for less. Stores like Target and Wal-Mart are in competition with each other and neither possess a unique asset so they are naturally worried about how their prices will compare to the other's.
I would like to see which store puts more money into government lobbying and campaign financing, and also which corporations CostCo is tied to and how they interact with political figures.