A classic camel's hair or a god simple tailored coat and a dual-duty raincoat will be of use spring, summer, and fall for many seasons.
If only one fur coat or jacket is possible on your budget, let it be a dress coat - preferably three-quarter- or full-length, with a shawl or roll collar. Mink in good quality is a long-term investment.
Every wardrobe needs at least one good wool or tweed tailored suit. It should be cut on classic lines, so that with minor shortenings and lengthenings from season to season it will be good for from five to seven years - or even longer. A good tailored suit should cost usually at least seventy dollars and be sufficiently conservative in color, line, and fabric that it is entirely unremarkable. A tailored suit is a uniform.
Too sheer blouses look just as bad as too delicate shoes with tweeds. A slipover sweater or wool shirt or some heavy fabric with body is best with tweed for the country. In the city a simple, non-sheer tailored blouse with a round collar or a turnover collar on a shirt neckline is most appropriate. White is usually best, or soft pastel tones, but avoid brilliant contrasts which destroy the effect of the classic suit which should be unremarkable.
From Amy Vanderbilt's Complete Book of Etiquette 1954