Okay, so you're not exactly negotiating "with" the thermostat, but with other members of your household. I had a discussion with a co-worker yesterday about this very problem.
I was telling him how I was interviewed last week by USA Today about lowering your thermostat to not only save money, but to lower your carbon footprint and he asked me how he can keep his thermostat low. At first I didn't know what he was getting at, but, apparently, his girlfriend likes to keep the thermostat at 74 degrees when she visits. At a minimum. He's happy with it at 68 or lower.
I suggested that he get her a Snuggie for Christmas so she had portable warmth. And to make sure she kept a pair of slippers and/or fleece jacket, etc. at his house. We talked a little bit more about his dilemma and then I told him that we use a space heater to warm up the rooms that we are in rather than heating up the whole house to a higher temperature. We saved about $800 last year by doing this. He remembered that he had a space heater stored in the garage and was ecstatic to try that out on her.
I hope I helped him resolve the issues he has with keeping his girlfriend happy and warm without having thermostat wars. And prevent risking that she not come back over again until the spring thaw. It's always amazing how these sorts of things cause strife in relationships.
Do you find that you are playing thermostat wars with your kids, roommates, spouse or others? Is it a losing battle or are you making any progress in convincing others that you can, indeed, survive in a house that is kept at less than 70 degrees?