My dad opened a few night clubs in the Myrtle Beach area, and they have been pretty successfull, but as with any seasonal place, it is hard to keep up business during the off season. I believe that is not too big a problem in the Chicago area though. But he took a few cuts on it for the first 5 or so years, and has now recouped his investment, and has been steadily making some easy side money (as an owner), recieving a yearly check in the mail that is quite substantial.
If I was you, I would realize that you will not see any profitable gains, but breaking even, for the first couple of years (probably about 1-5 years), it just depends on one thing PUBLICITY.
Do alot of radio ads on the type of demographic stations you want, ie if you don't want a thugged out crowd, watch on the hiphop heavy stations, and if you want an older crowd, hit up the classic rock crowds and all that.
Also keep in mind that College kids will always spend money on alchohol and are always interested in the next hot club, so do alot of College specials, ie free admisison with a college id, or drink specials on Natural LIght.
If you want any more detailed info, PM me, but I dont' want to post alot over the net.