Our trip to Chicago is not until next month, so I can't vouch firsthand for any hotels, but here is what I have discovered from my recent research;
Omni Hotel - currently has a great deal going on where the 4th night is free. I'm not sure how long you are going for, but if you plan to stay long enough it could be a good option. The hotel gets great reviews and is supposedly in a good location but the suites are small - 400sqft. It won't work for us with 4 kids, but could be an option for just 2 kids.
Hampton Inn & Suites - Good rates, but the hotel is supposedly across the street from a firehouse and it can get really noisy at night. I originally booked there but have canceled that reservation after reading multiple reviews mentioning lots of sirens all night.
Homewood Suites Downtown/Lakefront - The hotel gets great reviews for c/s and is supposedly very family friendly. I got a AAA rate of $197/night, which is the lowest I have found for a suite that is large enough and has a full wall separating the bedroom from the LR area. It is supposedly clean and well maintained but wallpaper is a bit dated looking. This is where we are currently booked and hoping it is fine, but I am still searching to see if any prices go down as it gets closer to the trip.
HTH
DS - 10
DD - 8
Twin Girls - 6