You may not believe it after seeing this chic fellow, but various schools of thought assert that no two of these colors work together.  This fellow is looking quite good with all three.  Some believe black trousers cannot be worn with brown shoes and others say black can never be combined with navy except for navy trousers with black shoes.  The contrast between these neutral colors is seen as too minimal.  This finance student, back in Beijing from attending university in Australia, makes it work very well though.  Perhaps those rules only apply to more formal attire.  The navy trench coat is real Burberry and the suede monkstraps are apparently made in Italy.  Most of his items are purchased abroad, where the price of quality is lower.