I have a lot of coats, as with all items of clothing, well more than necessity or decency should allow. The current favorite is this classic tan duffel coat:
Gloverall. Dig the chain loop.
When it gets really cold and really windy, few things protect as well as a coat like this. Down filled nylon high tech ski clothes do the job too, I guess, but I'm not a fan of clothing that can be legitimately described as "technical". Sure, this big piece of wool smells a bit like an old dog when it's wet, but it keeps me dry, and I could loose an elephant in the pockets, they're that big.
A duffel coat is also one of the most versatile cold weather options out there. On casual days, in a sweater and jeans, it solves the problem of being a long coat for casual wear, where a three button overcoat would be too dressy. Alternately, it works just as well over a jacket and tie when outdoor commuting in the city is in order.
I bought this one for $12.99 in a thrift store on the hottest day of last August, but Gloverall still makes them exactly the same for 265 GBP (approx. $410), a worthy investment I must say, given that mine is likely thirty years old and still going strong. Added points for the fact that Gloverall will sell you a full set of replacement toggles and leather strips for 7 GBP (approx. $11).
Best of all,
favorite scarf seems to have found its soul mate.