Here's what I do, and I use it literally all winter. I'm in the USCG, so I'm always out in the cold, then I go sit in a deer stand and try not to freeze haha.
Layering is the only way to survive. Your first layer needs to be poly pro, as it wicks moisture away. I've had great success even in sub-zero temperatures with the Under Armour Base 3.0 and 4.0 layers(the 4.0 is for colder temps).
Next layer is your insulating layer. What I use at work and for hunting is what we call a bunny suit. It's a 1 piece fleece layer that traps in your body heat. This is crucial. Here is an example of one, I'm sure if you google dry suit layers you can find more:
http://www.divers-supply.com/scuba/wetsuits/body-glove-undergarment-w-polartec.html#product_tabs_description_tabbed
Mine at work is really thick and the one I bought for hunting is thinner, but still works awesome.
The final step is to have a garment of your choosing that blocks wind and rain. At work I use a dry suit but hunting I wear whatever the conditions call for that day. Many times it is a simple as a pair of non-insulated Carhart bib overalls and a good jacket. I can sit on the stand for hours like this and not get cold. At work all we have is a dry suit over the 2 layers, and my body never gets cold even going 40 knots + on the bow of a boat in freezing cold temperatures.
For my face I wear a balacava that is camo. Something like this one, it needs to have neoprene around the face part. I've tried too many balaclavas to count and this one is the best around, I have multiples of them:
http://t.dickssportinggoods.com/product/index.jsp?productId=10881677&oldkeywrd=balacava
For hands I do a 2 glove system when gun hunting, with a thin pair of the under Armour gloves under heavier gloves. Not super happy with their liner gloves, but they will have to work until I find a different set. Also, the muff things you can strap around your waist and put hand warmers in May be the best $25 I've spent in a long time, I used it a ton this weekend
For feet I do a 2 layer system as well, with a pair of liner socks then good wool socks in insulated boots. I have poor circulation in my feet, so they still get kinda cold but I deal with it.
Sorry it was so much typing, but because of my profession and my love of hunting I'm always trying new ways to stay warm. I'm going to get a Sitka jacket and/or bibs once I save up some money for it.
Good luck!
