Check out the Montbell Thermawrap jacket.
At 8.5 or so ounces, it is featherly light, has a full length zipper, pockets for your hands, packs down really small, and is since it has syntetic fill it will keep you warm in damp conditions.
Two years ago, I replaced my bulky fleece with the Thermawrap and could not be happier.
I have taken it snow shoeing and winter camping as part of a layering system and I even use it in my sleeping bag laid over me like a blanket to provide additional warmth.
The workmanship is great.
Hope that helps.