I would not consider the imac screen to be a good source of facial lighting for facetime. We are using a small desktop lamp here, with an adjustable gooseneck extension. It works very well as a source of facial lighting with a 15 watt compact flourescent bulb. The flourescent lighting is great because it gives off a nice blue white light which works well with the built in iCamera. I suppose an ordinary incadescent bulb would work, although the lighting would be kind of yellowish.