For me, one of the advantages of the Kindle over Palm Pilots etc. I've looked at things on is that the lack of backlighting makes them easier on my eyes; it is more the effect of time with a book than time with a monitor or TV. One of the unexpected corollaries of this was that when I was struggling with a headache, going to bed with the Kindle and its light was easier on the said headache than going to bed in a normally lit room with a book (or, of course, a monitor or TV; that part does not bear considering in this circumstance).

The other time I will want the light is when reading in a hotel room with another person who has not yet awakened. Other congoers might find this relevant also, particularly those who are morning people like me.