Unless you intend riding in seriously sub zero temps, the same as you use in summer is the basic answer. The manual tells you the standards to look for in the oil, and the grade.
Everyone will have an opinion from the most expensive, to oil from the local chip van filtered through a pair of old tights. More expensive oils generally have better additive packages which is the part that 'wears out' in the oil, but not always. Be led by what you can source easily, and any special deals just now, but the choice is yours.