Go see "The Bean" in Millennium Park. That whole park area is great.
For tours, consider taking the Architecture Tour. It's conducted by a tour boat. I've not yet been there with the time (or weather) to do this, but it is supposedly the best way to see the city.
Downtown is full of great steak places. Take your pick.
Architecture tour and the Science museum are tha bomb. If you have time, there is a pizza tour that takes you to four very different places and they feed your face. It's really good. We got lucky, and the same company was offering a Prohibition tour where they again take you to several old speakeasys. You have to pay for drinks though. Fun little bit of history and food/drink.
Oh, and the Goat's Head under Michigan Ave. It's the inspiration for the old SNL "cheeboygy" skits.
First tip is don't rent a car. Take a cab. Parking is a veterinary term for a female dog. And if you drink, Chicago is an easy town to drink a lot in.
Across the street from Wrigley is a great sports bar called the Cubby Bear. They typically have great bands ... last time I was there I saw Little Feat.
If you like the blues, you need to go to Buddy Guy's bar "Legends". It is on South Wabash. Buddy will be on the road but Legends always has top tier blues live. Pretty good Cajun food too. When I lived downtown, I was in this bar three plus nights every week. Another great bar for blues bands is Kingston Mines on North Halstead.
If you like a steak that goes beyond great to magnificent there are several really good steak/chop houses in town. My favorites are Smith & Wollensky's, Benny's and Morton's.
With all you hear about "crime" in Chicago, I found it to be pretty safe. As long as you stay around the restaurants and bars, you will be fine. Go off the reservation and you can have problems.
Fawk Sear's Tower tour. Buy an overpriced beer at the 96th floor bar in the John Hancock building. Awesome view at night. Cooler building, too. I love the design.
Maria's Package Store in Bridgeport is a bar with a meat pie place next door. You can go in and order a pie, and they will bring it to you in the bar. Pretty awesome. Very relaxed/uncrowded in the day time.
Italian beef at one of the big names.
Field Museum. I could spend days there. My favorite museum.
Buddy Guy's can be fun. Buddy was there the time I went. Signed a picture for me, sang a bit, drank some cognac.
Second City shows are worth it.
No pizza. Chicago style pizza sucks.
Outside of a few particular neighborhoods you'd have no reason to go to, Chicago is as clean and safe as it gets for a large city. Public transportation is very efficient there. Get a train/bus card. Cheap, easy.