You can ride in the dark with dynamo systems. A 3 watt lamp can be bolted to the fork crown. You can't use them for emergency repair ilumination.
Bottole dynamos: Cheaper. Need a solid mounting point. Can clog up in mud.
Hub dynamos:efficient and reliable. Heavier and residual drag when not in use.

I have a handle winding LED lamp for general household/camping use. It is smal and light and gives several hours of illumination from a windup.