What type of headlight bulb is brighter?

Answer 1

There are three main types of headlight bulb:

Filament

HID

LED

Filament are traditional bulbs, using a metal filament surrounded by halogen or xenon gas. Standard bulbs are normal, but headlight bulbs of up to twice the brightness, such as Osram Night Breaker are also available.

HID use an arc of electricity, and are on some high end cars. Available as an upgrade, you need to add a ballast unit and a new bulb, so not a direct replacement.

LED is only just becoming mainstream. No upgrade path from standard bulbs, as they need carefully designed fittings and controls to make them bright enough for main headlights, although they are common in sidelights, tail, brake and indicator bulbs.