I think the "best" ones would be U of T, McGill, UBC, Western and WLU....BUT....for me it depends completely on the teacher, I know that WLU doesn't have the piano department that it used to have.
I chose my school based on who I would be studying with, and the opportunities that I would have. I honestly believe that if you have talent a school will do whatever they can to accomodate you, including sending you to other Universities for lessons, etc. And a smaller school can really showcase your talent. I don't know, I could be wrong, but it has been working VERY well for me. Good luck with your decision.