One thing that would be HIGHLY useful (and I can't believe no one's thought of it yet) would be a scheme to control groups of lights, a'la a track-lighting switch. Shouldn't be too difficult, just allow lights parented to a control light inheret all its settings, or something similar. It would drastically simplify extremely complex lighting setups in Blender.
One way of achieving the same effect would be to take one light and duplicate it using ALT-D to link the objects to the same 'lamp' ObData block. That way all the light objects would be an instance of the original lamp, taking it's settings from that.
You could also try something with dupliverts too.