The great temples of Upper Egypt were built on the riverbank, which is why a cruise remains the most comfortable way to see them: the boat moors, you walk to the temple, and lunch is waiting when you get back. Nothing is repacked between Luxor and Aswan.
Three quite different kinds of sailing are gathered here. Standard river cruisers run the classic route past Karnak, the Valley of the Kings, Edfu, Kom Ombo and Philae. Dahabiyas are small sailing boats that moor where the large ships cannot, at El Kab, Gebel el Silsila and quiet Nile islands. Lake Nasser cruises go somewhere else entirely, south to the Nubian monuments and Abu Simbel.