What is the proper temperature to set your home thermostat during the winter? I live in North Dakota and have been having an argument with various family members. Some 72 all the time, while others say turn it down to 68 at night. Is there a "proper temperature?" Is there anyone who can give me a definitive answer?

There is no proper answer. It is more about preference and how low you want to keep the heating bill. Also how well your house heats up. I hate being cold and my house is drafty. Sometimes I have to put it up to 90!
I have to cover the windows with plastic and hang blankets in doorways to keep more heat in the room I use the most.
People that say keep the temperature at 68 at night are reasoning that you can cover up with more blankets so you don't need to keep the house that hot. I say what about when you have to get 0UT from under them warm blankets... brrrrrrrrrr!