Wool
I am in love with wool. I wear wool socks all winter, along with "woolies," a thin, wool base layer, usually Merino. It's an amazing temperature-regulating, natural, traditional fabric that is widely-available and super-breathable, which means it hardly needs to be washed (and never dry it in a dryer!).
Book: Green Housekeeping
This book makes me want to clean my house and to take better care of the things that I have. Not only are the photos full of modern-rustic farmhouse charm, the advice is truly helpful. I also love that the cleaners are truly non-toxic (hint: most solutions involve baking soda and/or vinegar!) since I strive for a chemical-free home.