Aswan is where the Nile narrows between granite boulders and desert dunes, dotted with islands and white-sailed feluccas. It feels smaller and slower than Luxor, and the river is the main way to get around: to the islands, to the Nubian villages and to the tombs on the far bank.
It is also the heart of Nubia. Nubian villages on Elephantine Island and along the West Bank, with their painted houses, and the Nubian Museum give a side of Egypt that most trips through the country only glimpse.
Aswan is the base for Philae and for Abu Simbel, about 280 km to the south, which many travellers visit as an early-morning day trip. With two or three nights you can see these, sail around the islands at sunset and still have time to sit by the water.