I've been to Egypt several times, have family there. It's a great trip, but try to go when the weather is cooler (any time after October). Try not to go in the early spring because of sandstorms.
You can go into the pyramids, but if you don't like enclosed spaces then don't do it. You will climb a ladder, stooped over, in a very narrow space, with poor lighting. There is also a small museum behind the Pyramids, the Sun Boat, that is a don't miss. The Cairo museum is wonderful, a lot of walking and very little information available at the exhibits themselves. I've heard they've updated the museum, but last time I went in 2002 there was little explanation as to what I was looking at in the displays.
Go on the Nile cruise if you can. See the Valley of the Kings, again if you can go in the winter time, it would be better. But, don't cut Cairo short. It's noisy, crowded, and dirty, but so alive and full of things to see that most tourists miss because they don't know about them. Don't go with a cheap tour company though, there are hotels in all of Egypt (not just Cairo) that are very scary.
I wish to go back to Disney, but I really dream and desire to go back to Egypt.