I have too often now seems men wearing ghastly shirts with their suits, operating under the delusion that any color shirt with a collar is appropriate for the workplace. Unfortunately, this delusion is perpetuated by too many modern clothing companies making these ghastly shirts to begin with, marketing them to men none the wiser.
In short, a man's shirting wardrobe should be based around two colors - white and light blue (remember that a gentleman always remembers to wear a tie that is darker than his shirt).
Now, within these two colors lie infinite combinations of fabrics- checks, stripes, and patterns.
Along with basic whites and blues, one should have smattering of the following colors: pink, lavender, yellow, and for more casual shirts, tattersalls with red, green, and brown checks.
Colors that should never be in a man's dress shirt wardrobe:
I open the table to discussion, gentlemen!