What hotel charges should I be aware of?

i booked online at the o'hare hilton in chicago. they charged me $20 for taxes or something. but i'm uming you've already paid those. i've stayed many times in chicago and the taxes were never that high. phone calls will cost you an arm and a leg, take your cel. room service has charges added on, gratuity and service charge. there shouldnt be anything else that they will 'get' you for.