Chicago is a truly wonderful city. Make the time to do the boat tour that the architectural society runs on the Chicago River, which is quite enjoyable and very educational. Eat a deep-dish pizza (and know going it it will take 45 minutes to arrive at the table after you order it). Go see some live jazz on the south side of town. Take a walk on the lake front and go stroll on the Navy Pier.

CTA trains are the easiest way to get around, or just walk. Do NOT rent a car, unless you're a big fan of getting stuck in traffic and paying a fortune to park 17 blocks from your destination because that's the only space you could find after circling around for almost an hour looking for a spot. Taxis can be hit or miss - they're fine, but they get stuck in traffic just like everyone else.

O'Hare is a fairly painless airport to transit, all things considered. Weather delays in winter (snow) and summer (electrical storms) can be a pain at times, but in October you'll be fine.

You may want to check your dates to ensure you don't overlap with the Chicago marathon ... you'll face intense competition for restaurant tables and hotel rooms from about 40,000 other people that weekend, and the road closures on race day make getting around pretty much impossible. If your trip does coincide with the race, go cheer on the runners and make the most of it, because you won't be going anywhere till the barricades come down.

Chicago is awesome - enjoy.