Pittsburgh wants to replace all 40,000 of their streetlights with LEDs starting this year.

  I think we will see this happening in larger extent. And not always it is a nonsense: LED's do have lower efficacy then their discharge counterparts, but they hold court in three aspects:

With proper luminaire thermal design their lifetime is equivalent or longer then lifetime of a streetlight itself, so they need nearly no servicing.

They emit light only in "half-globe" without any optics. This simplify the optical design, so when not screwed up, the optic will have higher efficiency, so the system efficacy difference is not as bad as "paper" lamp parameters look. Furthermore this optic might be in the form of a lens molded around the chip, so no dirt might accumulate to block the light.

They don't care about frequent switching and/or dimming, so adaptive lighting control is feasible, so lanterns will be ON only on places and to that amount, where they are momentary required, so most places (mainly quiet residential areas) will be dark during late night, yielding much less light pollution and lower electricity consumption (even if LED's are less efficient then HID by themselves)

I am running a Terralux in my minimag, have been for the past 3 years and it is AWESOME!  i only have to charge the batteries maybee once a month and it is bright!!.  However the incan can throw the beam just a tad bit further..

I have a 3 watt Mag LED bulb in my 2xD Mag light I keep in my car.  With cold (>0°) half-dead batteries it's brigher than the incandescent bulb with room temp fresh batteries, and it works pretty well with the Mag optical systems too.