NURB: exactly, your milage will vary. Here is Energystar’s suggested schedule:
http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=TH
They suggest lowering the temperature during the work day (when we are away) and at night by 7-8 F.
It is notable that this was developed before modulating furnaces with multiple stages. It sounds like Nurb has the pimpest of systems.