Lots to choose from poly, merino wool, fleece, etc. Is UA good yeah, are they over priced yeah, is there other stuff just as good yeah. A base layer of poly/merino high neck garment, under a fleece/merino layer, with a windproof top layer is what I use. it helps to have zippered garments to adjust to changes in body temp. No cotton including socks. I use that in some combination from 50 to -20.