How has Ancient Egypt contributed to our collective human identity and heritage?

This is a really broad question and one that could be interpreted (and refuted) in a number of ways so I am going to just touch on some main points.
In the broadest sense, Egypt is one of the world's ancient civilizations and had a deep impact on Africa, Europe, and the Middle East. Its temples and monuments represented leaps in monumental architecture, geometry, and astronomy, and they set the stage for increasingly large-scale architectural works.
In terms of agriculture, Egypt had advanced land reclamation projects and brought desert lands along the Nile to life. This allowed the civilization to flourish. Without large agricultural projects, Egypt would never have grown to the size that it did or command such a large empire.
Its hieroglyphic system of writing was also an impressive feat, as was the accounting of its history told on the walls of ancient tombs and papyrus parchments. Papyrus was an early type of paper and represented a key step in the eventual development of books.
Lastly, Egypt served as a measure by which other civilizations from the Romans to the Persians measured themselves by. And its role in Judeo-Christian traditions is huge as it was from Egypt the Jews fled led by Moses, who was later said to have been given the ten commandments by God.
As you can see, there are many different ways we can say that Egypt influenced human identity. On a secular level, I think its impact in terms of architecture and geometry were among the most profound; on a religious level, its role in the story of the ten commandments and the later impact these had on the West was pivotal.
http://www.bbc.co.uk/history/ancient/egyptians/egypt_importance_01.shtml