That's probably why I've been thinking about coats for the past few days.
If a man is to have only one coat, it unquestionably should be the classic tan, double-breasted trench with a removable liner, which also makes it suitable for warmer wet days in late-spring and early-fall:
My last two have been from Burlington Coat Factory. My latest one is 11 years old, and about due for a replacement. I have my eye on this one from Jos. A. Bank, and I'll probably pull the trigger sometime this fall (as I recall, last Black Friday, they were $99; the typical real ["sale"] price is in the $200 range).
The second coat should probably be a similar one, in a lighter weight, and with either no liner or the liner permanently removed. (Removing liners is a hassle, and this will allow you to have a second tan trench, designated solely for days when it's too warm for your winter one). For variety, it could be a singe-breasted, balmacaan style:
For my taste, this particular coat is a few inches too short; dress coats should always extend a few inches below the knee, to around mid-calf, both for the aesthetic reason that shorter coats look too boxy and top-heavy, and for the utilitarian reason that a longer coat keeps the legs warm and/or dry.
To reiterate, the first raincoat (or winter coat with a waterproof, raincoat-style shell) in the wardrobe should be tan. Basically, the only other acceptable colors are navy and gray -- but only as a second or third coat. Anyone unfamiliar with John T. Molloy's research on black vs. tan raincoats should buy his book, Dress For Success, which can be found on Amazon for next to nothing.
In addition to my winter coat from Burlington, I also have a lightweight, unlined tan no-name-brand trench, purchased at a thrift for $2.00 (yes, $2.00).
I also have a similar-weight, unlined tan balmacaan from London Fog, acquired at a thrift for $10.
And, just a couple of weeks ago, I scored another lightweight, unlined balmacaan from Austin Reed, in a medium-gray with a faint yellow windowpane plaid, also at a thrift for $10.
I also have a heavyweight, lined navy trench with wool collar from Stafford (J.C. Penney, seems like better quality than their current offerings, I suspect vintage 1980s), bought at a thrift for $4.00.
What can I say? I like clothes, and I like variety -- and, at those prices, how can I miss?
Once you have a heavyweight tan trench and a lightweight tan trench or balmacaan, your next dress coat should be a wool-like (wool, camel hair, cashmere, combination, etc.) coat, ideally double-breasted (for style and extra warmth).
The quintessential version is a tan polo coat, like this one from Polo Ralph Lauren (a Polo polo):
In my opinion, while this is beautiful, a navy or gray version is preferable first, both as variety from the tan trench and to have a coat for more somber occasions, when needed:
(This gorgeous version is also from Polo Ralph Lauren; unlike the tan version, it's 100% cashmere, and also features a ticket pocket. I believe that this is the exact coat written about by Richard Merkin in Esquire Gentleman about 20 years ago.)
Of course, this advice can't always be followed perfectly by those shopping the second-hand market. I don't yet have a navy or gray version; my only one is also tan, from Polo University Club (an inferior Ralph Lauren brand from about 20 years ago, not as nice as the full Polo version above). I bought it on eBay 12 years ago for about $175, and it has served me well every winter since.
To me, a dream coat wardrobe would be (in addition to the heavy tan trench and unlined tan trench or balmacaan) versions of this double-breasted style in tan, chocolate, navy, medium gray, charcoal gray, and olive green, plus two herringbone tweed balmacaans, one brown and one gray.
I'll leave casual coats as a subject for another day.