Having an attractive front door improves curb appeal and conveys the message that the home is looked after.  A fresh coat of paint will personalize and perk up your front door. Since it is only a small painted area, you can afford to be a little more adventurous. There are no fixed rules, but I suggest a color that contrasts and complements the color of your siding and trim. Get some paint samples and paint a board at least 2ft x 2ft so you can stand back and look at the color from a distance.  Pale colors tend to make the door disappear. Try deep hues that add depth and draw the eye.