Saving money with my boiler?

Is it better to leave my boiler/baseboard hot water heat at a constant temp like 65 degrees at nite and around 60 during the day when I am not home better than just turning my thermostat right off during the day? I have heard different opinions that it takes more energy to heat the water back up to a certain temp than it would to leave it at a constant temp. To me it seems that shutting it off would be better because it isnt apt to run at all during the day when it needs to cutting back on gas/energy. Thanks!