I went to Cairo once, a year after 9/11. I was nervous about how I would be received as an American. I found that while people in Cairo might disagree strongly with the U.S. government, they were extremely friendly on an individual basis to Americans - especially if you learned a little of the language and respected their basic customs.
Cairo was an incredible mix of old world and new, with a fantastic sense of history. Luxor was one of the most impressive sites I have ever seen.