Chicago's low on the Meetup-based list, but I wouldn't characterize it as a poor area for gamers by any stretch.
For one thing, we've got Games Plus, where Buzz & co. put on a very well-attended EN World Game Day every few months. Games Plus is a real gathering place for RPGs, CCGs, wargames, and miniatures, and the place is almost always hopping. If you want to meet gamers in Chicago, there's one right there.
Me personally, I'm in two different D&D groups, as well as being involved in the area's active RPGA/Living Greyhawk community (and, Chicago's in LG's Verbobonc region, which many consider one of the better-run regions in the campaign). In the 18 years I've lived here, I've never lacked for gaming opportunities.
About the only negative I can point out is that we don't have a significant gaming convention here (probably due to the prohibitive cost of convention & hotel space here). OTOH, we do have a Wizard World con, several smaller conventions, and GenCon Indy's only 3 hours down the road.