Personally, I'm a bit of a foodie, and a lover of fine beers, both of which Chicago does very well. For a really nice meal (kinda pricey), hit up Graham Elliott in the city. If you like Sushi, then I can't recommend Indie Cafe in Uptown highly enough. Also, can't beat the dogs at Weiner Circle if you're looking for a Chicago experience.
If you like beer as well, I would recommend you check out Two Brothers in Warrenville, and/or Goose Island on either Clybourn or Clark, it's all good!