I disagree with the Philips Ambilight concept of backlighting. The bias light should be constant, not automatically adjusting; and pure white, not multi-colored.
The purpose of bias lighting is to reduce eye stran. Eye pupils dilate and contstrict depending on the levels of light. When viewing TV in a dark room, the eye has to go from a bright spot in the center of vision (bright scene), to pitch black (dark scene), and the pupils adjust accordingly. Eventually, the eye muscles become fatigued, causing eye strain and headaches.
The solution is a constant bias light behind the display, so that the light fluctuation in a dark room is kept to a minimum. As a result, the pupils do not dilate too much even during dark scenes, because the bias light provides the additional lighting that will prevent the pupils from dilating in the extreme.
An ideal bias light should be a pure white light, so as not to affect the purity of the colors on a calibrated monitor. The idea is to present a neutral color, which can be achieved by using a bulb with a color temperature of 6500K, more or less. The color of the wall behind the screen should also be neutral (white or a neutral gray), so as not to affect the 6500K color temperature of the light cast on the back wall.
As for the brightness of the bias light, the usual recommendation is 5-10% of the total light output of the display. Similarly, the SMPTE (Society of Motion Picture and Television Engineers) recommends a backlighting of less than 10% of the peak white output of the display.
If you like the Philips Ambilight concept because it looks cool, then that's fine. But if you're interested in calibrated color accuracy, then you should look elsewhere.
(Ideal-Lume is the industry standard:
http://www.cinemaquestinc.com/ideal_lume.htm)
