Determining what style of lighting you will use depends highly on your subject, and the final end use of your image.
-High key portraits, for example, would be great for a NASCAR driver. It would be an effective way to light the subject but also showcase the sponsors. Pure, clean, minimalist, and elegant are words that come to mind with high key lighting. High key lighting for commercial portraits is often used by brands that are associated with sophistication.
-Low key portraits are great for invoking mood and tension. Using shadow and light- you can create mystery for your subject. It is an effective way to photograph actors, musicians or any other character. All it has to do is fit the specific ambiance that you want to create, or follow the brand vision you have from your client.
Which do you prefer? Let me know!