I'd add that Giza is a big area. Around the train station you are close to the metro but nowhere near the pyramids. Up near the pyramids, there's nothing much to do or see except said pyramids, and at rush hour (which lasts quite a few hours in Cairo) it can take a very long time to get back down as far as the metro station in order to get downtown or anywhere else more interesting, although there are also busses that take the ring road and may be a bit quicker.
Faisal street in Giza is full of fascinating urban life and enticing-looking cheap restaurants, though!
