Have to disagree with the Underarmor. The compression fit actually keeps me warmer. Really doesn't restrict blood flow. Everyone in my family said how much it made staying in the woods even better. Most were wearing thermals prior. You should be able to comfortably move and it does not restrict movement. If it does, it is too tight/small.
I would have to respectfully disagree with cotton as a first layer. When damp or wet, cotton provides no insulation value and will just make the cold feeling worse. Just remember the saying "cotton kills". Put on a wicking type sock liner and then a good wool sock or two depending on temps and wiggle room in the boots.