[Jujubees2]

I've had one with National Grid Energy (used to be Brooklyn Union Gas) for the furnance and hot water heater. It's about $275 a year and covers all emergencies (with parts) and includes one yearly cleaning. As Hotub mentioned, one service call would more than cover the cost (though I've been fairly lucky and haven't had to make many calls even though my furnace has to be 20-30 years old).