OK- you've all done it!! I went to the thrift store and bought 2 wool sweaters. They're a teeny bit itchy, and not very pretty, but HOLY MOLY I'm sooooo warm when I wear them. I bought a thin merino wool one to wear under my cycling coat and a thicker wool one to wear in our house (it's always cold).
I honestly didn't think that wool would make a difference, but I'm sold now!

Thank you for all your tips and advice. My torso has never been warmer. Someday soon I'm going to get some wool tights and then my legs will be just as happy as my torso.