I'm in NJ, so fairly mild winters compared to many folks. Year long riding is possible for those of us who prefer to ride, aside from occasional snow or ice. Typical winter temps for morning/evening commute will be high 20s to low 30s for the morning commute, highs could be 30s-40s, and evening commute somewhat less cold than the morning commute. Whenever it's not raining in the morning (or there's not salt left on the road from yet another apocalyptic storm that didn't happen), I ride to work (and may or may not get wet on the way home).
I typically wear:
Under Armor cold gear socks
TCX Hero boots
Jeans, Freeze-Out long johns, underwear
Short sleeve undershirt, flannel or dress shirt, Freeze-Out shirt over that depending on temp, Mega Force leather jacket with liner
Wind blocking neck sleeve and sometimes wind blocking under helmet cap (never had a balaclava that didn't fog up my glasses worse than normal)
Cheap $20 winter riding gloves that are stiff but reasonably warm
Bell Bullitt with bubble visor
My top half stays reasonably warm but all those layers are very bulky, and wind sneaks through my zipper though it's not as big an issue with the wind blocking shirt underneath. Helmet is breezy but I worry a less breezy helmet would fog up even easier. Bottom half gets cold but tolerable. I don't mind having an extra layer when at work, it can be chilly inside. I'd like to be warmer on the bike and less stiff in the hands and for shoulder checks.
I'm thinking some insulated over-pants may help, or an insulated bib could shave a layer off the top and help mobility. Maybe a winter suit I could easily put on and take off over top of everything else. What do you guys like for winter gear? What setup works for you?