The struggle in wintry countries is that you need a whole separate work wardrobe and footwear collection for the season, which due to the expense, you may spend an entire part of your career building up. Here is a review of the different kinds of winter boots that I would consider staples.
Winter Ankle Boot
The winter ankle boot should be sturdy, either low / block-heeled or a wedge, with a sole meant to provide traction on ice and snow. It should be mostly waterproof, insulated, and actually meant for cold weather. (Inserting liners into fall boots may not do the trick.) This boot is supposed to be demure and downplay the fact that it is a winter boot at all. A boot like this goes with wide and straight leg work pants, tights, double the tights…

Over-the-knee Winter Boot
The over-the-knee winter boot is essential for layering. It allows you to forgo snowpants even in the biting wind and cold when doubling up on pants or tights doesn’t cut it. Hopefully it comes up to above the edge of your winter jacket for a desirable wind breaking effect, as this London Fog one does for me.
This boot again needs to be sturdy (you do not want to twist your ankles walking to meetings), insulated for the cold, and it is a bonus if the back side of the boots are made of a material that is easy to wipe down (slush, salt etc). They must not be slouchy as you don’t have time to constantly be pulling them up in a blizzard.

The Real Winter Boot
While living in Canada generally may require investing in the joan of arc Sorels at some point, it may be useful to have a winter boot for work that can get you through a foot of snow in -20 to -40 degree weather. These boots will be heavier and will come with traction. So you need enough arch and foot support so that you don’t hurt your feet.
Face freezing rain much? Consider crampons and avoid skating on the sidewalks.
There are more and more options for stylish choices in this department – look for form fitting structure, a little bit of detailing and unique designs and colours. Saute Mouton from Quebec is unparalleled in my books for the combo of function and style. But Sorel, Cougar and La Canadienne make good boots and have good offerings.

While I selected these boots with a work wardrobe in mind, hopefully you are not needing to trek around in the heavy duty winter boots all day and you are able to switch into other footwear once you are indoors. That said, the ankle and over the knee boots are ones that you should choose for being appropriate for indoors as well – when you can’t or don’t have time to change into something else.