I often ride with a neck gaiter. As the neck tends to be the only peice of exposed skin with out. In the summer I MIGHT ride with a bandana tied around my neck.
When it gets colder I would use a balaclava. Most do not work too well. Thick flece ones don't fit under the helmet well. Thinner more wind resistant ones tend to fog the windsheild or goggles. The best one is this type. The one wiht a very thin head covering material.