In real cold weather, 10or less, I wear UnderArmor thermals under fleece lined jeans, and then my 1 piece insulated hunting suit. If I'm going to be doing a lot of hiking, then I'll skip the fleece lined jeans. It seems to me that good fleece is the warmest. Even in gloves and hats. I had a awesome wool jacket/ pants that was very warm but i out grew it years ago.