I'm an American. I know no less than 5 Canadians who don't even know there is a Canadian queen (and one who adamantly denies it). That being said, I'm against it for a bunch of reasons.
A 2004 survey (conducted every 3 years) estimated the 'cost' to the Canadian people at $49 million per year. This is obviously in Canadian dollars, but does not take inflation into account.
It is also my understanding, which is pretty limited, that the GG is appointed by the queen, based on the advice of the prime minister. The last time anything that could be called 'royal veto' was used in 1961(in the queens name) when a lieutenant governer refused royal assent to a bill. It's clearly not an everyday occurance.
Also, it's probably possible (though it's never been done) that she could sign a bill that would otherwise NOT come to pass. This assumes the GG denied it, or a Lieutenant Governor did. I.E. _SHE_ can give 'royal assent'. Lastly, she has 'diplomatic immunity' (by way of she cannot be tried in her own courts) when she is in Canada.
I dunno, I just think that you guys should 'oust' the queenie. It only takes a constitutional amendmant, and well... the queens signature. I certainly woudln't sign something saying I wasn't king anymore.
Oh, one more thing, through the GG she holds the power over the entire military, but that's not really her power to wield.
Maybe hold an election, and decide who the Canadian Royal family SHOULD be. A lottery perhaps, and each citizen recieves a ticket, and the winner is the queen (or king). Hell, even a talent show would be a better way to figure who rules. Seriously though, I don't think she's even a little necessary, and there are whole organizations already devoted to getting rid of the title.
Also, Charles will inherit the title when (if?) the queen dies, and no one wants him in charge of anything. On the plus side though, if he dies and Camilla inherits the title, problem solved, the queen is Canadian. (and VERY distantly related to Celine Dion and Madonna

)