Different light bulbs typically require different mounting types – the reasons for the existence of so many different mounting types are long and varied, but generally boil down to licensing issues.
Once you commit to a particular light bulb type, be aware that you will have to keep using that style from then on so pick one that is common, otherwise finding replacement bulbs may be a challenge. Also try to use the same mounting style throughout your home – it makes it a lot easier when it comes to replacing important bulbs in a hurry.
Weatherproof and underwater light mountings
Specially sealed mounts to prevent water from coming into contact with electric lighting circuitry.
Bayonet cap (BC) light mounts
These push-and-turn mount types are hold the globe in via small bayonet pins, and are very common in Australian homes.
Bi-pin light mounts
These mounts are common for downlights, and are found in many homes as a result of the popularity of halogen globes.
Cable and rail light mounts
These types of mountings are particularly common for areas with high ceilings and where movable task lighting is needed.
Edison screw (ES) mount
This mount type is also extremely common throughout Australia, and features a familiar screw-in mechanism.
Fluorescent tube light mounts
A variation on the bi-pin mount, these are designed for mounting fluorescent tube lighting.