re: Would ISIS blow up the pyramids?

The answer is no. ISIS would need the support of the Muslim Brotherhood to achieve this. Blowing up the pyramids, or even mentioning this, would have them in a war against the Muslim Brotherhood, the Egyptian Military and the remnants of Mubarak's dictatorial regime. The one common ground between the Brotherhood and the Pan-Arab Nationalists is their admiration for pre-Islamic Egyptian civilization. The Muslim Brotherhood views Sharia as the perfection of ancient Egyptian civilization and the Pan-Arab Nationalists see a unified Arab Republic as a continuation of ancient Egypt's glory, where Western imperialists no longer control its territory and resources. ISIS would be fools to underestimate the reverence that Egyptians, even fundamentalist Salafists, have for their history.