Arc’terx Gamma MX Hoody would be #1. This jacket will do much more than just keep you warm, it will REALLY keep you warm.
I was a little skeptical that this lightweight jacket would do the trick when cold and wind are howling. But I wore this on a recent backpacking trip to the Shendoah National Park, and climbed to 3,200 feet in 20 degree weather. Let me tell you, I was pleanty warm. The MX Jacket’s Storm Hood is now helmet compatible, so your noggin is safe and warm at the same time. Another improvement is the longer body, which blocks drafts and keeps you warmer. The Gamma MX is highly water resistant and extremely breathable.
When I wore this jacket, I brought along my hard shell, but soon took it off and the Gamma was all I wore. This jacket makes an excellent midlayer or insulator when snowshoeing in the Winter. This will be a big part of my Winter gear from now on. Even if it’s a light rain, this jacket will hold true to being water resistant.
Breathable, wind-resistant, lightweight Polartec® Power Shield™ face fabric
Scholler® Dynamic reinforcement fabric along chest and pockets
Full coverage Storm Hood™ adapts to most helmets
Trim, athletic cut
Gusseted No-lift underarm sleeves minimize exposure during extended reaches
Interior wind flap behind full-length front zipper
Laminated left sleeve pocket
Dual chest pockets with laminated zippers
Dual high volume handwarmer pockets
Laminated hem drawcord
Weight: 21 oz.
Review the Arc’teryx Gamma MX Hoody[ratings]