Broken lighting in Blender file I'm having difficulties with a Blend file: 


Point Lights and Area lights are almost invisible
Sun, Spot and Hemi lights are functioning normally


By 'almost invisible' I mean that I have to crack up the intensity to 100.000 to see a dim shine. Preview pane at this level is completely blown out, as well as the entire scene if I switch to Sun, Spot or Hemi.

Does anyone have any idea what I'm doing wrong here?

A simplified file can be found at 

Thanks for any pointers you might be able to give.

Warner
Have you played with the "Light Falloff" node?
Just add the node into your light material and try the different falloff types.
  

But you can go further if you play with math nodes. First you need to understand how to build them:

Constant falloff : same strength everywere, no matter if you're close or far from the emitter.
Linear falloff : strength decreasing with the distance (strength = 1/distance).
Quadratic falloff : same as linear but decreases faster (strength = 1/distance²).  

Now we can play with math nodes to get tweaks and lower strength values.

I'm using your file but I had to fix your plane (removed doubles and useless perpendicular face)