Here's my "system":

Duofold expedition weight polyprop/wool long undies.

polyprop sock liners

smartwool or omniwool socks

Columbia wool pants

light merino wool sweater (goodwill is your friend)

heavy merino wool sweater

wool mackinaw (Asbell wool)

wool parka

Sorel caribou boots at least 1 size larger than normal

wool mittens that fold back

hothands handwarmers in boots, mittens, front pockets