Quote Originally Posted by mbeach
If everyone had HIDs, no one would notice -or care.
That may not be true. About a year ago, there was a study that claimed to show that humans have some sort of instinctive compulsion to look more closely at light sources in the 4000K-5000K range. That unless they actively tried to avoid looking too closely, people just naturally spent a lot more time looking at those lights than the more yellow ~3000K lights like halogens.

I'm sure I have some of the details wrong, because I am too lazy to go hunt down a citation right now. But it was my impression that this reflexive behaviour was not specific to headlights, but any light source in that temp range.