RE: boots
Grams of thinsulate such as 200, 400, 1000 is the amount of insulation and while the manufacturer specify this relates to warmth...it really don't. I wear 800 grams of thinsulate boots for hunting, ice fishing, skidooing and all winter long. I like boots that are warm, light but not hot, my 1200 gram rocky's are the coldest pair of boots I own and thus don't wear them...why they are too darn hot & heavy for my feet causing them to ring of sweat in only a few minutes. If your feet don't sweat than 1000 or 1200 are a good choice, if they do than 600-800's are better IMHO. Gortex or similar is a must IMO, wet feet are cold feet. Gortex is waterproof and breathable which is very important to warmth. However I agree the stuff you put next to your feet is as/more important as on your feet. I use polyproplene sock liners(moisture wicking) and a top quality wool sock. Some find the fleece socks great as well.