It is much better to bring along either a canteen, or some other utensil that will allow you to carry the water bottle on your waist or around your shoulder. Fanny packs or backpacks with holders for water bottles, and for women, even a shoulder bag type of purse will make this more convenient. Most tourists will be doing a considerable amount of walking, and shoes should not be just comfortable, but comfortable to walk long distances. Unlike leather shoes for mountain walks and such, it is also preferable for walking shoes to be breathable and perhaps made of a lightweight nylon or similar fabric. Also, keep in mind that there are a lot of steps in Egypt.
Power Adapters come in two different varieties.
Some electronic equipment have switches to allow you to change the power input type. For these, a simple wall adapter is all that is required. However, other electronic devices do not have such switches and in this case, you not only need a wall adapter, but also a power converter. Egypt uses 220 volt and plugs are two prong rounded. It will usually be available in Egyptian drug stores, but it may be called a different name.