Lights

Whats the difference between halogen lights and xenon lights?

the gas inside the light it's self
other than that I don't know which one is easier on the eyes to drive with, or which one is more efficent.

Where I live it's illegal to switch to xenon bulbs from halogen, although I'm sure that will change if they find that xenon are safer.

none are illagal here, my friend bought a hid kit off of ebay and those puppies are extremely bright, I would hate to drive in front of him. But anyways I need to replace my head lights and I believe I want Xenon ones but then they get confusing with the kalvins, you can get 5000 to 8500 kelvin??