We've been to Egypt twice - we did a Nile cruise which was lovely, and saw all the attractions below the Dam, such as Valley of the Kings, and on the next holiday we stayed up at the Marriott hotel at Taba Heights and we went and did some excursions from there,and went to Petra, which is well worth seeing.
We haven't got to Cairo yet, but may do, some day. Incidentally I booked both of these holidays about a fortnight before we went, one through last.minute.com and one was a Daily Mail offer - both between £450 - £550 for both of us - the cruise was virtually everything included. Don't drink the water - or have any ice cubes! my OH, who normally has cast iron guts got ill the day after he had had ice in his drink, which may be pure coincidence, but I still wouldn't trust the water. have a great time, whatever you decide to do.