Hi Lee,
I had a fantastic time two Januarys ago in Egypt. I was on an organised tour for 16 days or so, and it was an unbelievable experence. Other then 200 bucks US for our guide, I paid everything in Egyptian pounds, and regularly got cash out of
ATMs when I needed it. And well I did do some bargain hunting and in the end need some extra cash after buying plenty of cool gear. I went a little "native" and grew out my beard, and wore a gallabayo and headdress around for most of the trip, the locals loved the fact I went the extra mile and were very welcoming and friendly. During the trip I later shaved the beard and wore more western clothing and they were almost just as friendly. At no point did I feel in danger or threatened, but being a big bloke I got the impression it could be a bit different with females, as culturally they tend to treat women different. I'd definitely advise to consider their culture and dress appropriately (no short shorts, or miniskirts), exposing so much skin is frowned apon and may drawn unwanted attention.
From a tourist standpoint.
Cairo is a cool city, the traffic scare the crap out of you at first, but by the end I was walking through 6 lanes of traffic like a local. Definitely check out the Cairo museum, if you can visit the Coptic Christian area, or the bigger Bizarr forget the name.
Valley of the kings is cool but I would think 3 or so tombs is enough, you don't have to do them all. We rode donkeys from the Nile into the valley of the kings, definitely an unforgettable and fun experience. If you can get out to a local village you can really mix it with the locals and get a better feel for what life is like outside the bigger cities.
Abu Simble is definitely worth the visit.
From a photography perspective there is some great subject matter, if I went again I'd shoot more portraits of the locals. There is a big tipping culture over there, and 1 or 2 dollars will get you some willing subjects, with the kids most are just happy to be the centre of attention for a short time. Be aware some places are off limits for flash, and the very occasional place off limits for photos but its very rare. I used the 18-200 most the time, and a little with my 10-20 but not as much as I expected.
If I can think of anything else I'll come back and let you know.