The Sound-and-Light-Show at Philae is like a symphony of illumination. One walks along, listening to a tape telling the legend about Isis, Osiris, Seth, Hathor, Horus, the Nile and the history of Philae.
It is so beautiful, I could go there again and again. You have to take your time, it takes a while to listen to the tape while enjoying the changing of the lights.

Only disadvantage: To visit the main temple inside and marvel at the beautiful reliefs at the walls, you will have to come during the day.