Rick Bayless has one of the best mexican restaurants in the country in Chicago. I've always wanted to eat there.
http://www.rickbayless.com/restaurants/grill.html
might be a bit pricy, but they do lunch....he won Top Chef masters, and had a long running cooking show on mexico
looking at the site, it seems he has a new sort of take out place called XOCO...i'd bet anything he does is tasty