One tomb is the reason most people come: QV66, cut for Nefertari, the principal wife of Ramesses II. Its painted decoration is the finest that survives from ancient Egypt — figures modelled in a way no other tomb attempts, colour that looks a few years old rather than three thousand, and a ceiling of gold stars on deep blue over every chamber. It was conserved over several years by the Getty Conservation Institute working with the Egyptian antiquities authority, and the result is genuinely unlike anything else you can walk into.
The queen's tomb is not the whole valley. The tombs of two of Ramesses III's sons, Amunherkhepshef and Khaemwaset, are usually open on the standard ticket and are worth the walk on their own — the reliefs show the boys being led by their father through the gods of the underworld, and the colour in them is strong.
It is also far quieter than the Valley of the Kings. The valley itself is small, bare and hot, and most tour groups skip it because Nefertari's supplement puts it outside a standard package.