Honestly, Chicago made me disappointed in New York City. The Architecture is unbelievable, even to the person that doesn't normally appreciate architecture. Chicago just has a different feel than any other city I've ever visited. Walking down Michigan Avenue from the Wrigley Building to the Chicago river to Lake Michigan... the views are just unbelievable. It's not a city to walk with your head down... that is for sure.
The Architecture center:
875 N Michigan Ave
They offer guided architectural walking tours of Chicago at 2 for $24... they have a huge selection. They also have a variety of bus tours and cruises. The store located at the Architecture Center has a great selection of gifts for the guru, like myself... playing cards, books etc. It's located across from Grant Park on Michigan Avenue... very easy to find.