For me it's mostly just the bite on my face and runny nose. I use Schwalbe Marathon Winter studded tires on my city bike and the design of the bike makes it fairly impervious to slush or other problems since everything is internal and protected. I occasionally wipe it down, more for aesthetics than anything else.

I have segregated paths everywhere I go (and don't go places that don't provide physical protection once it snows) and the counties and cities do a good job of keeping them clear. Worst for me is some intersections and parking lots when the snow is heavier than plows can keep up with.

I wear normal street clothes and am comfortable down to about 15-20f.