put a pair of latex gloves in your repair kit. sub zero or peeing it down punctures at 6am are a little more bearable and still easily manageable with them on. a little single aaa battery or button cell torch you can hold in your mouth too is not a bad idea, saves on your bike light power and allows you to manipulate the illumination a bit more than gagging on a cree T6 would ;-)
Lighting, forget the helmet cover gimmick and put a set of to be seen by lights up there too - urban or rural it is an early warning system to others over the tops of adjacent cars or hedges. If you don't fancy them on your hat, always have more than one set on the bike. For a lightweight but still good option, I found last year throughout the winter my cateye volt 300 on brightest setting was good enough for pitch dark unlit country park and countryside roads - i am a pretty slow pootler though, if I were racier I'd want a brighter light I think to be totally happy, it was also very good on dual mode in more urban traffic. Just seen they've brought out a volt 700 - i imagine that would be more than enough for any dark road & speed.
I carry a pair of the single LED on an elastic band, couple of quid from Tesco, lights too as a total failure get me home seen backup.
I like stuff that screams cyclist not delivery driver or jogger so I totally +1 the Sam Browne belt over dark clothes - best level of contrast and no ambiguity it is a person on a bike. if you don't already & can, use pedal reflectors (I have some Shimano platforms that clip into one side my SPD M520's). When I'm driving, the orange uppy downy motion is very apparent and especially on country roads with no pavements, they do immediately make it click that the person is likely to be further out into the carriageway than reflective trainer detail does.
I put a reflective slap band round my right wrist too to act as an indicator for going across traffic.
buffs are brilliant for a range of neck and head covering. Coats are too bulky unless you really do feel the cold usually, a couple of layers and a soft-shell has seen me right without looking like michelin man or boiling in the bag. My best bike buy ever is a windproof vest, if you can find one you'll love it, it makes loads of difference to how little you can get away with wearing and still be warm and comfortable down past zero.
