The John Hancock building offers a beautiful view of the city and lakeshore. There is a restauramt/bar at the top of the building which has the best view and is a quick elevator ride to the top.
You must go to the ladies bathroom which offers a fantastic view like you will never have coming out of a bathroom stall.

when visiting dont pay to go the observatory level, just go to the bar & get a drink, it will cost you about the same & you can relax in a seat!! =]

Been to the lounge plenty of times, but unfortunately my Y chromosome doesn't allow me access to the women's room. Still great views all around.