Well, since Rick Bayless just won Top Chef Masters a few month ago...my recommendation would be Frontera Grill for brunch on Saturday because they take reservations. YUM. It's completely loud, and therefore kid friendly (at least for my son:-), but not nearly as busy and minus the wait that can occur in the evening. Plus,it meets your criteria, you can only find it in Chicago and it is definitley not snooty or pricey. (We have been there at least ten times since my son has been born and we are never disappointed.)
Another thought, Chicago Pizza and Ovengrinders on Clark. Really yummy food totally unique pizza pot pie and cool story (started by two lawyers who didn't want to practive law anymore.)
Have fun!