The Dry and Warm crowd subdivides yet again into two categories: Synthetic Material Lovers and Wool Snobs. Both materials wick moisture away from the skin and evaporate it effectively.
Wool has the added bonus of staying slightly warmer, even when wet, and tends not to get as smelly as many synthetic blends do after extended use. Layering on top of this base layer is an art that requires balancing temperature regulation and too much sweating.
The key to making this system work is to wear exactly enough clothing to stay warm without producing too much sweat. Excessive sweat will soak the base layer and, depending on the ambient temperature, it may never dry, causing rapid heat loss once the activity intensity has slowed down or stopped.
For moderate activity, a base layer and a soft-shell jacket will suffice for temperatures well below freezing as soft-shell jackets tend to breathe fairly well.
For bottoms, many companies are starting to make wool shorts that add an extra bit of warmth. A pair of baggy mountain bike shorts will go a long way towards blocking the wind in sensitive regions.
A pair of Nordic skiing pants will also breathe well and block the majority of the wind on the legs. As the temperature drops, a set of light long underwear under Nordic ski pants will generally be adequate down to 0 degrees F.