It is extremely unlikely that Egypt will end up an Islamic theocracy if this revolution is successful. "If" being the key part. I am extremely sceptical as to whether the US government will let a puppet government like Mubarak's topple to be replaced by an actual democracy, particularly since Egypt is the second largest receiver of US aid, right after Israel.
"If an injury must be done to a man, it should be so severe that his vengeance need not be feared" - Niccolo Macchiavelli