I spent a week with my girlfriend in Egypt, visiting Cairo and Luxor. We visited during Ramadan which everyone thought we were crazy to do - but in our opinion it is the best time to visit. Fewer tourists, everything still open and we even got to descend alone into one of the Geiza pyramids!
I recommend splitting your stay up into two parts when in Cairo and staying at both of these hotels.
We tried a few local restaurants, but came up short with good food. The best food we found was at restaurants close to the Sofitel Hotel - not local food, but good food.
In Cairo it is very cheap to get a quality guide and driver. I recommend doing this because you will be safer with a local, and hearing all the history when looking at those grand monuments is invaluble.
Travel blogs filled with all you need to know based on personal experience.
I didn't do it, but these are great references if you are looking for tips.