A Salomon Acti-Therm zipneck running jersey is my current favourite cold-weather base, 4 way stretch, fleecy inside, with mesh armpits (awesome!). The horizontal pockets with tiny invisible zippers at front and back hem are perfect for batteries, Bic lighters, ProBars, whatever I want to keep warm. Those pockets are so useful for winter backpacking that once I had them, I wondered why my other winterweight baselayers don't.
I can't find it on the website now, but from MEC I have an incredibly lightweight zipneck pullover made of a very thin windproof laminate material, with thin stretchy underarm panels, which does very well as a windshirt.
Both these layers have long cuffs with thumbholes, another useful feature that's more common on running gear than on hiking clothes, for some reason.