I've watched the forums regularly, and haven't seen a thread where our biggest concerns are thrown together, a lot of threads offering some of those concerns, but not all at once.
Having commuted through winter for a few years now (has it really been close to 10 years?) I have experienced a lot of the effects of winter riding and how to counter it, but my biggest concern are my feet and my core temp. I hate when my feet get so cold that they are almost numb, and prickly. It hasn't happened in a while, it did a lot on my 50 mile commute, mostly on the ride home with tired feet from standing all shift.
I have had my core temp drop twice, and it was really fing scary. It made me think about those below 0F days, and did I really need to be out in that sort of weather. I learned how to keep it at bay, like not drinking cold fluids, or take a break and stand around letting my body cool down, while drinking a cold water bottle, two incidents that I'd been like the dude in Jeremiah Johnson, frozen with his rifle still in his hands.
Okay your turn.