Here's maybe a way to answer the "What should I eat in Chicago?" question, since it's usually impossible to answer without knowing more about the person's wants (fine dining? THE Chicago pizza?).
If YOU had charge of a visitor between flights at O'Hare (like Calvin Trillin with Chairman Mao), and they could only go eat one place, where would you take them? (By putting the question that way, I hope to encourage a diversity of response instead of ending up with basically a poll for the best pizza or Italian beef.)
So. Three hours to kill and a limo. Where are we going?