LED lighting has a lot of applications, the main delay has been the cost along with the constant improvements in efficiency, colour temperate replication, etc. The Seat Leon was the first car I believe to have complete LED lighting with no type of discharge bulb being used.
Another recent application was the Queensway/Chad's tunnel refurbishment in Birmingham that has replaced all it's lighting, another benefit of LED is that it's car more consistent and uniform, creating a consistent level of intensity.
However, it's not a complete replacement for traditional HID. Concerts for example, the main place LED has come in, well first it was the video aspect which has reduced the size of and weight of panels, meaning it's easier to put a bigger show on without out more trucks, more power, more weight allowance etc, along with maintaining a great pixel spacing & resolution for audiences. With lighting, they are mainly being used as alternative to stage washes. Washes don't need to be focused, or to controlled. But they need to change quickly and be controllable, which they are.
What they haven't replaced is traditional intelligent spot lights, you can't put a sharp edge on traditional lighting, make it pencil thin or suddenly make it a fat star effect. Just an example, Muse's recent arena tour.http://www.eventindustrynews.co.uk/wp-c ... C_0149.jpg
The bottom lighting providing the red wash are all Mac Aura LED Fixtures, everything coming are traditional luminaires, MAC Viper's I believe, which are recent new product.
I'm not familiar with the exact specs or LED/HID lumiaries, the power used, the colour temperature ranges, the lumens, etc. But I know in most cases, IE architectual lighting among other applications, there is a strong case for LED.