Oxford is needed in every closet, since it is the most formal and serious shoe made for a suit, brown is most versatile.
It is common that men under utilize the brown oxford shoe. Black shoes are commonly seen and worn almost as a rule where a brown shoe can add style, flair and make the outfit look smarter. Never fear wearing brown with dark colors, no matter the shade of brown, it goes well with any color suit.
The men that do wear brown with darker colors, usually wear a dark brown shoe. This is quite acceptable and looks good, but personally I prefer the light brown or tan shoe. I especially enjoy a modeled brown shoe with colors ranging from tan to dark brown. I think a modeled brown shoe is the most versatile shoe made since it picks up all shades so well and it visually interesting. It is also a shoe that improves with age and time, growing character and becoming more personal.
Gray suits, no matter the shade, are benefited tremendously from the brown shoes. It brings out the richness of the suits fabric. Enhancing the colors and adding an interesting pop of color at the waist and at the shoe.
Navy or Blue suits and brown shoes are a natural, in my opinion. Blue and Brown go well together and the colors enhance each other well. I think that black shoes actually take away some of the color and beauty found in a navy blue suit. I would only suggest wearing black suits with a blue suit in only the rarest occasions when formality is mandatory.
Brown shoes even work with black. Brown shoes and a belt pop with a black suit, highlighting the craftsmanship of both. While I generally do not condone a black suit, this is a great technique to send focus to the shoes and belt.
Keep the brown shoes with only minor brogue work and a beautiful and sleek last (a term referring to the shoes silhouette) and they can be worn for almost any occasion with any suit. Brown is much better than black.