Ramadan is a great time to visit a Muslim country. don't forget Egypt isn't just about antiquities but also about the people and the culture. Over 80% of the population are Muslims the rest being Coptic Christians and even the most lax and laid back make a special effort during Ramadan
Effects on tourist visiting sites - none what so ever, drink what you like, eat what you like, smoke what you like. I think it is nice not to smoke in a car when the driver is fasting but actually I think it nice not to smoke in a car full stop. Some drivers are very macho about their fasting and like to show how strong willed they are.
Effects on tourist in hotels - none what so ever, often the Christian staff do day time and Muslims night so don't assume everyone you see is fasting
Availability of alcohol - reduced during Ramadan although this is generally sold by Christians it does stop during Ramadan and strict Muslims will not handle it. 5* hotels are not affected.
Effects on tourists non tourist sites, banks, etc these often keep different hours during Ramadan generally closing for Iftar (the sunset meal) so just remember to go early in the day
Effects on tourists traveling, if you have a private driver and are traveling at sunset do suggest he stops to break his fast otherwise no effect what so ever
Interesting things to see
those better off supply food for Iftar in the streets for the poor, it is quite amazing seeing all these roadside camps, you may be offered something there is no problem accepting, just have a couple of dates
family meals, if you get invited to Iftar go, some of the meals are fabulous, the best cooking happens at this time, they try and break the fast with dates
all the old TV programs get recycled, some have subtitles but anyway it is fun to watch the over the top dramas
the mad race on the roads to get home for Iftar and the dead silence on the roads during Iftar
the lanterns, lights, flags and paper mosques put up by the children to decorate their homes
everyone in the country united in celebrating a religious event. This is the aspect I love. Everywhere you go being offered good wishes, people supporting each other, the children excited doing their first fast (they start off doing half a day fasts and it is a big event). Not everyone fasts, sick people, nursing mother and small children do not.
So don't be put off visiting because it is Ramadan, join in the celebrations