I think that La Moraleja and Pozuelo / Somosaguas are probably the best options for the expat / school side of things. But they are not near the centre, in fact they are not even Madrid city, Pozuelo is a town in its own right and La Moraleja is in Alcobendas.
If you want to be close to the city, you could try the area around Puerta de Hierro, I don't know it that well, but there are some spectacular houses around there.
But as Chopera said, it does depend on budget. I could not afford to live in any of these places, but if for example you have an expat package worth several thousand € / month, you could obviously pick and choose!
If money was no object, I personally would choose where I wanted to live based on where I would have to work, then choose a school nearby. Not the other way round.