Curran's gym for sure, but if you are operating within city limits and can't easily get out to the suburbs, I'd suggest the Chicago Fitness Center in the Lakeview neighborhood. Mike Russow used to train there (don't think he does currently.) Shonie Carter trains there sometimes. There is a subset of hobbyist/weekend warrior types, but you can get good training if you put in effort. Some guys there fight pro/am, smokers, grappling tournaments, with decent success.
