AS others have said, layers are the key. I've used a variety of liner gloves over the years - surplus wool, wool/ploypro blends, all polypro, and lately powerstretch - which I think I like the best. I do carry two pairs of liners, for two reasons: one, I lost a liner glove on one trip where I just happened to have two pair because I was trying out some new ones, and two, on another trip I got the one pair soaked and was glad to have a spare. So now two pair is my standard. The powerstretch liners will dry fast if shoved inside your shirt while you're on the move.
I like to have wrist cords on my mitten shells so I can take them off and not drop them or have them blow away. The shells I have now, OR Goretex paclite, have wrist cords on them and that's very handy. My first rule of winter handwear is never put a glove or mitten down anywhere except in your tent. Put it in your pocket or in your pack or shove it inside your jacket, never put it down; if it blows away you're in trouble.