Not too bothered about cold temperatures - I only draw the line when I wake up in bed and can see my own breath. Went most of two winters ago without any heating at all in Uni, mainly to save on money
This past winter at my own house was awful though; so hot that I comfortably slept with the window wide open in freezing conditions outside. At home I live in the same house as my elderly grandparents, who have the downstairs (where the thermostat is located) and like to have the heating at about 27-29C. Just before the winter we had cavity wall insulation and enough lagging in the roofspace to lose a flock of sheep in, so that means the heat can't get out of the house, but that it can pass upstairs to my bit of the house - meaning I boil whilst they turn it up a bit more and maybe even put the gas fire on as well!

Whilst staying at my girlfriends though it's a bit different - middle of nowhere on a peninsular into the Atlantic Ocean, crap boiler and an expensive and crap fuel oil heating system, meaning it's normally chilly even in the summer. I don't mind though - I'm happy to sleep starkers ontop of the covers whilst she's wrapped up in about four blankets - I just don't feel cold that badly.
Dan