Hi! So urban planning programs are usually very flexible - you need to find out what areas of urban planning you are really interested in. I applied to 4 schools and got into 3 of them. If you are looking at US schools, then MIT, UIUC, UC Berkeley, UCLA, Rutgers are pretty good. If you are interested in Environment and Sustainability side then you might like Berkeley's program (it doesn't have an international focus though and it is very California-centric). Rutger is good for transportation planning. MIT also has a concentration in Environmental Policy and Planning. UIUC's Community Development for Social Justice concentration is pretty good, if you are interested in marginalization, displacement issues in cities. Similarly, MIT's International Development Group is pretty good if you are interested in urban issues of the Global South. There is a lot of work being done in sanitation, water, health, climate change, spatial analysis, urban information system at MIT. If you are interested in urban theory then MIT might not be the best fit for you.
I also applied to UCL and LSE in London. Check out UCL's Bartlett School of Planning - you might find something that interests you. LSE's program of City Design and Social Science is more sociology plus urban design oriented.
Do look at the subjects offered and thesis of current students or alumni for the schools you shortlist. It will give you a good idea of what the program is all about. Also look at research interests of professors.
(If you go to MIT, you can take courses from all over Harvard and Tufts as well!)
I don't know anything about Canadian schools, though