I am tempted to try and do the same for Canada, because all of these US-exclusive lists are rather misleading. But we Canadians hate to brag about anything, so... Unfortunately, I do not have the recent and thorough-going experience that would enable a really accurate evaluation of music schools, so I will just sketch out a few possibilities.
1. McGill University Schulich School of Music
Despite long-standing budget problems (ameliorated by a very large donation a few years ago), McGill continues to be what is probably the finest music school in Canada. It has a student body of close to a thousand students which enables the formation of three orchestras: a full symphony orchestra, a chamber orchestra and a Baroque orchestra. The standard of performance is very high and the school is also known for its outstanding programs in musicology, theory and composition. The school presents hundreds and hundreds of high-quality concerts every year including this one being presented today.
2. University of Toronto School of Music
Though they would like to think of themselves as number one, the U of T School of Music, though with a larger student body, does not seem to be on quite the same level as McGill. They have some fine ensembles, like the Afiara Quartet, associated with the school and along with the Royal Conservatory of Music in Toronto offer an impressive range of programs. I don't have enough personal knowledge to say much more.
3. Université de Montréal/University of British Columbia/University of Victoria
Here is where it gets really sketchy because these three all have fine, though different, music schools. I'm not sure how to order them as they are so different, so I am giving them a three-way tie. The Université de Montréal is a French-speaking school that does a lot of very innovative and fine things. It is where a lot of the very accomplished Conservatoire students go if they feel the need. UBC is a large school on a very fine campus and UVic is a small school on an equally fine campus. UVic is particularly renowned for its piano performance program, which is one of the finest in Canada. It has also produced a number of fine composers. UBC is a much larger school with some fine faculty members.
4. Conservatoire du Québec
This is a quite different kind of school, based on the French conservatory model. It has a number of branches around the province and the teachers are paid and provided benefits similar to those of civil servants. There are recent reports that there will be some severe budget cutbacks. The Conservatoire has produced some of the most accomplished performing musicians in Canada and you can find its graduates in orchestras coast to coast. Students can attend from an early age and by the time they are eighteen, are already accomplished musicians. Music is rather different from the other kinds of disciplines taught at university as to be an accomplished performer you really need to start serious study much earlier--for the violin, for instance, starting no later than seven years is probably advisable.
After this there are a host of fine university music schools in places like Brandon, Manitoba, Antigonish, Nova Scotia, London, Ontario and other kinds of music schools like the Banff Centre and the Victoria Conservatory of Music.
Which school you choose will depend on the particular kind of program you are seeking and, most importantly, what teachers they have that would be suitable for your needs.
If anyone wants to quibble about these admittedly sketchy rankings, please use the comments to do so!
Here, from the McGill Symphony Orchestra's program, is the Brahms Symphony No. 2 with the Vienna Philharmonic conducted by Leonard Bernstein: