Well, as everyone has said, Don't Use Cotton!
My cold weather gear is as follows:
Feet:
poly sock liners, wool socks, 800-1000 gram boots and foot warmer packs - there are new ones with insoles that work well. Dont use them in moderate weather or walking to your stand as it will make your feet sweat. I will put them on at the base of the tree. If your feet get wet, your done. If you have a long walk, use one layer of socks and then change at your tree. The 10 minutes that your feet get cold changing will be worth it for the next several hours that they are warm and dry. davidmil has good advice on keeping your boots roomy. Tight fitting boots make you feet cold.
Lower Body:
Underarmour cold gear, mid-weight poly or ECWS thermals, regular camo pants and insulated bibs. Spring for some nice weather proof bibs. They will block the wind and moisture and keep your mid-section from being exposed.
Upper Body:
Underarmour cold gear, mid-weight poly or ECWS thermals, regular camo shirt and insulated parka. Throw some heater packs where your kidneys are if it gets real cold. If your jacket does not have a pocket for this, make one and safety pin it in there.
Head/Neck:
Underarmour cold gear baclava and hat. If it's real cold I'll throw on a fleece baclava over the UA and use another neck gator. You gotta keep your head and neck warm or your sunk.
Hands:
Depends on the situation.
Bow - Usually use a glove liner and throw some heater packs in my jacket pockets. I have one of those hand tube thingies that goes around your waste but my hands usually get stuck trying to pull them out. It does work well to keep them warm though.
Gun - Glove liner and one of those convertable glove/mitts. Put a hand warmer in the mitt part and when you need to shoot, just flip it back.
I also do not wear my jacket while walking to my stand. Try to keep sweating to a minimum. Move your toes and fingers. You can do this without attracting attention. If you get cold, make sure the area is clear and stand up. Just the movement while doing this will help a lot. Once standing, tighten your muscles without moving. (isometrics) I have used this system while hunting in the single digits to low twenties.
I think I am going to spring for some fleece or wool pants/shirt after this season. Hopefully they will be on sale.
Hey david, where is the ASAT 3D leafy suite over that cold weather outfit? I'm going to talk to Len.