I'm curious about what thermostats people are using. I also though I'd share the best one that I've found in my own research - the Carrier Debonair 33cs071. I got mine off of eBay. It's a commercial thermostat with a bunch of great features: 1) It runs off of the 24Vac supplied by the furnace controller, so it doesn't need batteries. 2) The deadband - the difference between turn-on and turn-off - is programmable. 3) It has the ability to be externally set back. I use that to set all the the thermostats back when I'm heating with oil. 4) It has two-stage outputs - think of it as 'need heat' and 'really need heat'. I use that to control changeover to backup oil heat. 5) To limit cycling of the boiler, valves, and pump, they are programmable to limit the number of cycles per hour. 6) You can easily request a temporary override of the set temperature, after which it goes back to normal. For the gadget minded, I don't think it gets much better.