Safe over Slip
Perhaps the most important function of a porch light is to see where you are going so you don’t trip, slip, or stumble. Front doors are often preceded by stoops, steps, and porches that could become safety hazards if underlit (or if you are blinded by glare). This is not a particularly difficult concept to grasp, yet it is astounding how many porch lights actually have solid bottoms or candle-style bulbs on top that result in the least light going down towards the ground.
If I could only pick one light for my porch, I would look for a fixture that puts more light down to the ground than in any other direction.