RECOMMENDED GEAR-BASE LAYER
Thermal Top and Bottom
A good thermal top and bottom are worth the investment. SmartWool makes an excellent choice, but less expensive options are availible. Rule number 1: Don't buy any themals containing any amount of cotton. They should not be selling them as they will only make you colder in the long run.
I wear wool socks year round as they keep my feet from growing any type of fungas or itching. A good pair of wool socks can also be worn longer without smelling. Wool socks equal warm feet in the winter and healthy feet in the summer.