The different varieties of lighting fixtures include ceiling fixtures, side wall mounting fixtures, etc can be chosen as per one's taste and requirement for his or her bathroom. Also depending on the size of the bathroom, one can choose from a single light fixture to a couple or more lighting fixtures.
Uniform light can be expressed through various bodies, selected according to the size of the bathroom. For a small bath uniform light can be obtained with the help of two bodies of lighting arranged on either side of the mirror, and for a large bath the light may be obtained by using a lightning body affixed to the ceiling, above huge mirrors.
There is no rule such that the bathroom lighting should be provided only in the ceiling or is better if it is provided at the sides or on top of the mirror. One has to fix the bathroom lightings according to one's taste and the mood that he or she wants to bring into the room. Even for a small bathroom, people, these days, go for two or more lighting fixtures. Thus, lighting is the most important factor to be considered in any modern bathrooms.
So, for example, zone 1 is the wettest location, being around the bath and shower. Zone 2 is slightly less soaking, being just outside the immediate bath, shower and basin areas, and zone 3 is the furthest away from these sources of water. So if you're looking for designer bathroom lighting to create a well lit bath or shower area, look for zone 1 lighting, and for bathroom mirror lights and designer bathroom wall lights, bear in mind you'll need either zone 2 or 3.