I had the opportunity to stay at Cairo Marriott a couple of years ago. I can highly recommend both the hotel and Cairo.
Don't drive yourself. Taxis and guides are not too expensive and the rules of the road won't make sense to Americans. Traffic moves more like flocks of birds and there are surprisingly few accidents.
The hotel concierge has lots of info and recommendations. Food is great and the Egyptians were kind and polite.
thanks, we also stayed at the marriott in cairo in 2000 and again in 2001. We loved the historical aspects of the hotel/palace and the city/museums, etc. Don't miss the cairo museum, nile cruise,luxor and a trip to Abu simbel!! Wee found the hotel to be nice, clean, and exotic in the palace rooms and gardens.