On the topic of the Governor General (not for long, I promise), many a pedant has pointed out that she will not *actually* be head of state: that job is the Queen's.
What is more surprising is that this distinction actually matters. It's why the provincial and federal governments are equal.
It might not have been that way. It has often been observed that if you look at the original constitution -- the 1867 British North America Act -- the provinces seem subordinate to the central government. In fact, the relationship between the provinces and Ottawa is repeatedly analogized to the relationship between the Dominion as a whole and the Empire. Ottawa can reserve and disallow provincial legislation, and the Lieutenant Governors hold their offices at the pleasure of the Governor General, on the advice of the federal cabinet, just as the Governor General was appointed by the Queen on the advice of the Colonial Secretary.
On this vision, Canada was not quite a federation -- a state with two equally sovereign levels of government -- but a self-governing colony with self-governing colonies. The legal basis of this argument was that the Governor General (the embodiment of the federal government) was the representative of the Queen, while the Lieutenant Governors (and hence the provincial governments they embodied) were really delegates of the Governor General.
It was, however, that most imperial of institutions, the Judicial Committee of the Privy Council (see the sexily named Liquidators of the Maritime Bank of Canada v. The Reciver General of New Brunswick,  AC 437 -- not available on the Internet, apparently), that freed us of that interpreation, and made it clear that Canada really was a federation.
The theory is that both the Governor General and the Lieutenant Governor are equally representatives of Her Britannic Majesty (who is the "true" head of state, and when "in Parliament", the sovereign). So both the provincial and federal government are equally sovereign, a concept that was a bit hard for those in the British tradition (and Ontarians) to really swallow, but one that was necessary for federalism.
On the mind-bending fiction side, it ranks somewhere between the Trinity and the Copenhagen interpretation of quantum mechanics. But the idea that the provincial and federal states are equal manifestations of the same sovereign works. It is what has kept this accidental product of British imperialism together and functioning. So, next time some anagram-loving know-it-all tells you that the Governor General isn't really the head of state, you know, suck it up. For Canada.