I would say 21°C (70°F) by day (my wife would say 19-20°C/66-68°F), 16°C (61°F) by night and when not at home during less than a few days. If not at home during several days then 3°C (37°F).
My last winter experience has been concluded by the fact a programmable thermostat is a must. Our next change will be to have one, and use it
Currently we have the house divided in 2 zones with one program by zone. The program consist of "hot" or "cool" for each quarter of hour. At each radiator you configure the "heat level" for hot, but it's with a wheel graduated from 0 to 7 and doesn't correspond to a temperature. Usually the "cool" is about 3°C (5°F) under the "hot".
During the first winter in our house, we didn't had any problem. As the programs are 24h, during week-ends we had to manually put some radiators on "hot" in the morning and put them on "program" in the evening.
During the second winter in our house, because of our baby, the zone with the bedrooms had to be more frequently on "hot". Additionally, the weather was colder and more variable, it was then more complicated to correctly configure the internal temperature and generated an additional 200€ electric bill
(in France the you pay a bill every month, but they get the counter value only twice a year).
Last week-end we bought a programmer. The salesman said us it could be programmed by temperature, but in fact it couldn't, it could be programmed only by "hot", "cool", "cold" and "off"
so we get it back to store and we'll try again next week, hope the temperature will not make us heat the house before that.
Denis.