I've been living aboard my '80 Hunter 33' for almost 2 years now in the SF bay area. We don't get the kind of cold some of you are experiencing...rain is our issue not snow, but our damp cold is still cold. I have a bulkhead mounted Balmar (Sig) diesel heater and an oil filled radiator style AC heater. I use the AC heater mostly since the diesel heater requires cleaning every 12 hours or so (not sure why, but it peters out and dies if I don't)...which is a bummer since the diesel heater puts out more heat than the AC heater when it is working well. I save the Balmar for the coldest day/nights.
I use thick throw rugs on the sole to help keep my footsies from freezing, and wool lined slippers are standard indoor wear. My biggest winter problem is leaks. I need to rebed some deck hardware (on my summer task list) and am dealing with the leaks right now by stuffing cheap towels up into the deck/hull join where the leaks are. I toss the towels in the washer/drier occasionally and the leaks stay off of the cushions and the carpeting on the hull sides...works well and is only a minor pita to deal with.
I love living aboard...but then I've never been claustrophobic
which would be a prob for some in my narrow beam boat (10.5'). Storms are kinda fun as I sleep VERY well in a rocking wind tossed boat...kinda lulling actually. I've had to spend money on bungee cords to secure my neighbor's halyards from slapping around which definitely will keep me awake, but now we have a nice quite dock.
Life IS good