Cyfer

Recently I've been using Under-Armour outer wear for those days in the single digits or lower. I have to say I'm TOTALLY impressed with the current kit for those days it's so cold on the East (Ice) Coast that it cracks ice.

UA Sonic Jacket (light weight and super warm)
UA Flow Pants (The lightest warmest pants I've ever worn!)

*for super cold days*
UA Dervous Fleece Jacket
UA Hudo Fleece Pants
*underneath the outerwear for extra warmth*

First layers depend on how cold it is
UA Evo upper and lowers
UA Cold Gear 2.0 upper and lowers (so cold you want to cry)

As of right now this is the warmest I've worn blows TNF and Burton AK away, lighter than both and just as warm. So far I've been in these on days that range from 1 degree to -18 and I've never been cold on the lift or on the hill. If you've got an Under-Armour outlet near you it's easy to pick these up for a steal in the off season. I spent almost half sticker price around August. Right now you can get most Under-Armour outer wear for less than most other brands that cost twice as much. I have to say I've got no complaints about any of this gear. Check it out and give this gear a try you'll find it pretty warm.

On a side note I'm on Blood Thinners for life so I get colder a lot quicker than most people. If this stuff didn't work I would be the first to say it. Most times I rock Analog gear due to the street style influence and such but when it's so cold most people run for the lodge I've spent hours outside in my Under-Armour gear without ever being cold.