Paying with American cash gets you a slightly better exchange rate than the current official rate of about 3.8 Egyptian pounds to a U.S. dollar. The ATMs in the major hotels are the easiest and cheapest way to get money. Exchanging travelers' checks is another option, though the rate of exchange is a little less good. For cab rides, ignore the taxis lined up just outside the hotel door, walk a few steps down the street, and pick a slightly more battered vehicle. Stick to bottled water, avoid all vegetables and any fruit you can't peel, and tote Immodium and plenty of Handiwipes.
Sanitation can be fairly primitive outside the big hotels.
Before you leave home, establish your special Egyptian calling code with your long-distance telephone service provider. If you don't, you'll be stuck paying the hotels' exorbitant international rates. Even old Egyptian hand Denis Sullivan found the group bookings he'd made weren't honored because his credit-card charges somehow hadn't gone through. If you book a hotel far in advance, keep checking your room rate. If they hadn't, paying a cancellation fee and rebooking would still have given us a cheaper price.