Seriously though.. What are you in the market for? Whats your apx budget? It will help to better direct you to the right company.
Some guys are top notch media room installers with plasmas and surround receivers and there are a few kick@ss full blown home theater guys in the area.
There are TONS of companies that service Chicago area and the north shore so you wont have a problem finding the right company.
If you have a specific product in mind like a certain brand of speakers or projector then you might get a hit by searching their "where to buy" section at their website or calling them up.