programmable thermostats rock. i put one in our last place and it paid for itself pretty quickly. the last place sucked balls for insulation. one year i had plastic over all the windows just to save some money.
if you've got a lot of old windows, you should look into replacing them. old windows seal like crap, so they'll do the opposite of what you want with the heat (keep it out in summer, let it out in winter). won't be cheap, but it'll pay for itself eventually.
i keep the house at 68-70 during the winter, 60 at night and when we aren't home. summer time i never set the AC lower than 74, and it had to be extremely humid for me to get it that low. normally i'd leave it at 76 and turn it up to 78 when we weren't home or sleeping. sure it gets cooler at night than 78 degrees, but with the house sealed up, the humidity stayed out.
first house my parents bought had a wood stove in the basement. there was a fan installed in the basement ceiling up through to the hallway on the ground floor (rancher, no 2nd floor). we'd get that woodstove kickin off heat then turn the fan on. my dad always kept the house at 68 degrees, but we could get the the upstairs to 74-75 degrees with the woodstove loaded up. saved a lot on heating bills, just a pain in the ass sometimes to stay stocked with wood.