What temperature to keep thermostat on in the summer?

When at home, 76-78 is a good temperature to keep the air conditioning at. When not home, move it up to 84-86. This way when you are away you do not drive your energy bill up as much, yet when you get home you will not need to use as much energy to bring the temperature back to 76-78 (as opposed to turning off the thermostat when gone).