According to GQ, it is acceptable to wear dark brown shoes with navy pants. A lighter shade of brown, such as tan, is not appropriate, because men's shoes should be at least as dark as their pants. Refusing to combine dark browns and blues is considered outdated.
Fashion Beans suggests that brown shoes are far more versatile than black. Not only do they complement a wide range of colors, including greens, grays and burgundys, they also work with both casual and dress attire.
Oxblood shoes, which are reddish-brown, are also fine accessories for many colors of pants. They work as well as brown, but the color is bolder and makes a more dramatic statement.