I just got back from Egypt (Nile and Sinai) and enjoyed it quite a lot. For those, you travel in the near future, let me give you some advice:
Bring really warm clothes! We were freezing to death. It is fine and warm during the day, but it gets very cold at night and even in the south (Aswan) we had a couple of layers on and people who had not brought a warm jackt were really to be pitied.
Bring a sleeping back or at least a sheet. Some of the accomodation are not the cleanest and it feels good to have something between you and dust and bed bugs (particularly at Sharks Bay!) Plus you might need it on the train ride between Cairo and Luxor since it was very, very cold on the train!
For the climb on Mt. Sinai make sure to bring a head light. The last 700 steps are not too easy to climb - especially in complete darkness - and you will be grateful to have two free hands!
When you go to the Nubian dinner in Aswan bring a torch for the way back to the boat since the path is not lit very well.
Beware of thieves in the Hotel Indiana (Cairo) and the one near St. Catherine. Several members of our group (among them a former tour leader in Egypt!) were stolen clothes, make-up and other things from the room. I was stolen money from the room in St. Catherine (just a 10-$-bill, but still) and I am 100% certain that it was nobody from our group since I was the last to leave the room and the first to come back again.
When you get to Cairo and leave the hotel for the first time, it may happen that people come up to you, say that they are associated with Imaginative Traveler and want sell you tours, take you to their shops etc. Egyptians tend to be very pushy and hardly ever accept a single "No, thanks" (even in Arabic, which is La shokran") as an answer. Plus they are NOT associated with Imaginative Traveler. The best way to confront them is either play deaf (signing something in sign language) or repeat the No, thanks a couple of times.
Although there is some whistling and catcalling after western women, you are usually left alone as long as you dress properly and avoid eye contact. Dark glasses come in quite handy in this respect.
Always mention your husband (even if there is none) when an Egyptian guy starts talking to you and it is obvious that he wants your attention which you might not be interested in.
Be tolerant but set limits right away. Egyptians like to touch (probably not in a sexist way but since it is part of their culture and communication)your arm, your face etc. If you do not like it, tell them frankly, say immediately "Please don