When I lived alone, I almost never ran the A/C (I had an apartment built in 1939 so it was built for natural air circulation) and my heat was set at 60 in the winter. I would put up with a lot of discomfort to keep my utility bills down. ;)
Now that I share the house with Boyfriend, I've gotten a little more lenient, but we still keep the A/C at about 77. I'd like the bedroom to be about fifteen degrees colder, but I sleep well enough if I turn on a fan and kick off the covers.