We keep our house pretty cold. Usually it's on 63, but we'll change it between 60 to 65 depending on how cold we are and whether we have company.
Our thermostat is on the first floor, and our bedrooms are on the second floor. Since heat rises, we do not need to change the setting at night. Usually our second story is warmer than our first story, and we have 3 air vents upstairs even though the square-footage is 1/2 the size (or less) than the first floor. Plus, I have a heated mattress pad that I use to warm up my side of the bed.
We keep ours at 65 and don't change it until it is time to turn to turn on the a/c. We turn it off when it is warm enough that we don't need the heat to be running, typically in May and we turn the heat on sometime in Oct.