Well, you are right, since brown shoes look better with both blue and grey suits it does tend to make black shoes rather obselete, except in extreme circumstances such as a tuxedo. However, black shoes are just fine, and often look great with grey suits. Often times I will wear a dark charcoal suit, with a white shirt and a black and silver houndstooth tie, and sometimes i wear black shoes with it. i think a nice english tan shoe looks better, but black looks just fine too, and is more discreet. wearing tan shoes when your entire outfit is black, grey and white looks great, but people are definetely going to take notice of it.