There's no magic formula, but there is a basic one--base layer for wicking sweat away from the skin, a mid layer for insulation--the thickness of this layer is determined by the temperature, and an outer wind-breaking layer. More expensive pieces might have better cut, maybe better sweat-wicking quality, maybe softer on the skin, etc., but ultimately it comes down to those three layers.

As for hands and feet, I've been using chemical heat packs for anything colder than -5*C or so. Fingers, especially the thumb, are the most difficult to keep warm. The poor thumb is always separated from its siblings, and don't get the benefit of group heat, and unfortunately I need it separated to operate the brakes.