Lessons I learned this winter applied:

Studs are great. Buy some Nokians (both wheels) and be done. Yeah they're heavy and take some getting used to.

It'll rust. NOW. So I hose down my driveline with WD-40 just about daily. Others have their own methods. Get a spare chain in any case.

Fenders are a must. Have a little extra clearence and periodically spray 'em with silicone spray or cooking spray to reduce bits sticking.

Clipless are fine, just spray the mechanism along with everything else. I only had problems in deep 'mashed potatoes' snow.

Brakes: I run disk. Were I to run rim brakes, I'd experiment with having a small brush (handleless toothbrush, perhaps) clear the rim before braking. Just a thought.

I don't carry electronics except a WIRED cyclocomputer. Wireless got a bit dicey in the cold.

Some other things:
Up your light count and use di-electric grease on all electrical contacts. Seems to ward off problems and deal with the fact that cars aren't expecting you.
Get a helmet cover. Fenders or no, you'll be bathing in the road slop--head to toe.
Wear glasses all the time. For the same reason.

Anything else?