I mostly adhere to John Forester's assertion that "cyclists fare best when they act and are treated as drivers of vehicles."
The only time I ever call that into question is when there's crusty, frozen snow and slush in the gutter pans, and I'm in the traffic lane on my bicycle going 15mph, and an impatient motorist is bearing down on me from behind at 25mph. Or tailgating me and revving the engine.
In fact, if it weren't for cars, winter bicycling would be nearly as enjoyable as any other time of year.
Yesterday (Sunday, 12/14), I accumulated about 7 miles of bicycle riding on fresh-fallen or snowpacked neighborhood roads, with essentially no motor-vehicle interaction. It was fantastic!
Last night it looked pretty obvious that the snow is here to stay, at least for a few days. So, I took off the "skinny" (28mm) tires, and put on the "fat" (35mm, with tread) tires for the season.
This morning (Monday, 12/15) I rode up the street to the bus stop, thinking if it was brutal, I'd catch the bus on in to the office. It wasn't too bad, so I forged ahead.
I like to think that my life and health are more important to my fellow citizens, than 5 seconds of their commute time. But sometimes I don't see much evidence of that notion. (And the news coverage, mostly showing pickup trucks and SUVs lying smashed and upside-down, doesn't give me a lot of confidence in the skill and good judgment of those people I'm sharing the road with.) So maybe when the roads are treacherous, I'd prefer separated bike/pedestrian paths, just as a matter of survival.