Whenever we have had more than a 5 hour stopover we have always got out of the airport and done some sightseeing - Miracle Mile in Chicago, the stockyards at Fort Worth, walking around Boston, the Liberty Bell and Christmas shopping in Philly. I don't know why you didn't get out of the airport there? We had no problem and it really gives us a break, fresh air, stretch our legs and see something other than the inside of a coffee cup and the airport! Try it, you'll have a great time, so long as you give yourself lots of time.
In Chicago, within an hour of touching down you can be through passport control, rechecked your bags and be in a taxi to downtown. Chicago is a beautiful city, very vibrant, clean and friendly.
Pam