The idea that modern Egyptians (who are predominantly Caucasian) are descendants of ancient Egyptians is, I would wager, currently the most widespread view of the problem among scholars: Egyptian Egyptologists, Hawass foremost among them, are particularly vehement about this. Claiming that initially Egyptians were black Africans, but were later replaced with Caucasian invaders is an extraordinary claim that requires extraordinary proof. This is why an article entitled "Controversy over race of ancient Egyptians" exists on Wikipedia.. 

Caucasian does not mean "lily white" - most Caucasians are quite "swarthy" in appearance, and range in color from brown (in India) to pale white (in Northern Europe).

- Dennv