Well, Toronto is the sunny south compared with Montreal, but if I may suggest a few things that keep me warm and toasty (sometimes too warm) in the winter. You seem to be okay with body heat so I'll confine myself to extremities.
Because I wear a suit, tie and dress shoes to work and don't have changing facilities, I wear Morino wool socks and a standard pair of heavy Oxfords. I cover them with some Serratus boot covers purchased from Mountain Equipment Coop. They quickly velcro on and off and keep even dress shoes clean and my feet toasty warm.
I have many levels of hand protection but my maximum protection if a pair of silk glove liners also from MEC and some Pearl Izumi gloves. The secret is to make sure the outer gloves are not too tight with the liners on. I think the slack creates a thermal barrier.
Oh, also I usually don't start out in the morning if the temp is below minus 25.