Some other things I thought of...
We have down comforters for all of the beds. We found them fairly inexpensively (or at least inexpensive as far as down comforters are concerned) at Ikea back when we were living in a house without insulation. Boy, were we thankful for them back then! Even in California, winter nights can get pretty cold! While we now have insulation and central heating, the comforters allow us to keep the thermostat pretty low at night.
Flannel sheets along with the down comforters and flannel or fleece pajamas (hey, even *I* have a pair of footed jammies!) keep us all cozy. We also have several fleece blankets for when it's not quite cold enough to need the down, but cool enough that a blanket is needed.
We also each got a Snuggie for Christmas a few years ago when I found some for $5 each. As wacky as they look, they do help!