Getting the right next-to-skin layer is the first, and maybe the most important, step before going out into the cold, cruel world. The higher output your activity, the more important it becomes. What if your chosen winter pursuits are both cold and aerobic? The answer is Polartec Power Dry.
REI's heavyweight long underwear has been redesigned with PPD, and the material is two-faced in a good way; the micro grid inner wicks efficiently and the smooth outer lessens energy-sapping friction with additional layers.
The heavyweight women's bottoms are snug and stretchy, with flat seams everywhere for maximum comfort. They are thick enough to provide ample insulation, thicker even than the men's equivalent. The only catch is the narrow waistband, which is so thin that even the flat seam there feels like it sticks out a bit. If that doesn't bother you, they'll keep you warm and dry in the cold, and the look is sufficiently conservative that you could wear them as an outer layer if you really feel the need to vent.