I think that depends where in Canada you live. Quite frankly, London and Toronto are pretty well on par with one another including the exchange.
I have found that for certain products, things are much cheaper in the UK. For instance, you can get a BlackBerry approx. $150 cheaper in the
UK than here (this includes exchange and tax). In the horse world, I noticed that you can get horse blankets $200 cheaper (again, including exchange and tax) cheaper in the UK than here!