You can't go wrong with fleece.
I know a lot of people are saying wool - but last time I tried it, it made me itch. Maybe it's different now, but 10 years ago I couldn't wear it.
For layers close to the skin(Like socks) Merino wool is both washable and itchless. Ragg wool and Worsted wool are best as outer layers.
I have always had circulation issues and my fingers and feet suffer greatly even with -100 degree rated boots, until I found Merino Wool socks by Woolrich at Wal Mart. Look for 70 to 80% wool content.