I'd recommend the Holiday Inn Express in Hillside. It was about $100/night with all taxes included, and I believe they have a shuttle to and from O'Hare. I flew into Midway (which I would recommend), so I had to take a cab. If you take a cab, do not take one of the city cabs. They are a ripoff. Call up one of the flat rate taxi companies to come pick you up. They'll take you to Hillside for $30-$40, which is about half of what it would cost to take a city cab. The Holiday Inn Express is also nice because they have a free shuttle service which will drop you off at the medical school and bring you back to the hotel after your interview is done.