Much of my work in the aircraft industry has been with lighting. We are currently working on an all LED system for our newest offering. The control of this system is a huge pain in the ass. You need to account for different LED color, color temperature, brightness, aging, color drift, etc...
Another big problem is how LED's make light. All current residential fixtures/light designs are with omnidirectional sources. LED's create a single beam of light. It's tricky to get this light diffused in enough directions to create the same sort of lighting we are accustomed to.
In short, I don't think we will be seeing LED's breaking into the common lighting market anytime soon. Ten years? Sure... Five years? No.