Another dogma I have no use for is: "The shirt must be lighter than the suit and the tie darker than the shirt." Why? Sure, the black shirt and white tie combo looks pretty silly on anyone except a musical comedy gangster. However, I think a light-colored suit, e.g., tan or light gray, with a medium to dark blue shirt and, say, a pink or yellow tie can look very good in an appropriately festive context.
On second thought, probably the foregoing rule may have some validity with the stodgy dark gray or navy suits commonly recommended for business wear, but it should hardly be universal. Does anybody here have any views on this one?