I dress the same way I do xc skiing - as little as possible, poly next to skin if I'm working hard and moving fast, windproof but vented as much as possible on the outside. For lower intensity, og if I have to stop at times I wear thin wool next to skin, also if it's really cold because then the consequences of getting wet and cold are just a bit too dangerous. Wool keeps me warmer, but I don't like really working up a sweat inside wool. Wool is great as a midlayer too, though.
Today it's going to be -6 C (about 20F) and I'll be wearing bike shorts, extra layer of poly boxer shorts (against the Numb Butt Syndrome
) Amfib tights, mediumweight wool socks, winter shoes, sports bra, turtleneck poly shirt, Gore Phantom jacket, lobster gloves, Buff and skull cap for the hour-long ride to work. I'll feel a bit cold for the first few km.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett