Magic has been all over the world in various types of folklore. The fey of the Gaelic, the spirituality of the Chinese and Japanese, South America's Incas and Aztecs, the golem of Judaism, the shamans of Native Americans. Of which I personally think is one of the oldest, considering they crossed over to the continent via the old ice bridge that eventually collapsed due to continental drift and such.
There all sorts of ways that each of these schools could be top in their respective fields. Egyptians, though known for their curses on the pharaohs' tombs, are more known for their huge advances in medicine, crafts, and time keeping at the time.
As for curses, there are defensive spells and offensive spells. Knowing the best defense wouldn't mean knowing the best offense, inherently. =) Say your character knows hexes up the wazoo, but barely has an any defensive knowledge other than a basic protego, he/she could be easily overwhelmed by a spell that doesn't directly affect the user, but possibly the area around the target, like Transfiguration.