Nikon D5, Nikon 85mm ƒ/1.8G, ISO 100, ƒ/4, 1/200 –  Alienbees B1600, White Background & Lastolite Triflector silver/gold kit.
KISS – Keep It Simple Stupid
Keep your gear as simple as possible so you can concentrate on the people. For this headshot setup, I keep it super simple.
Here is the Lastolite-Triflector reflector that I am using for the headshots.
This helps kick light under the chin and into the eyes for what I consider a very flattering light. Now the main light is a beauty dish most of the time or a white umbrella. I prefer round light modifiers for the catch lights shape.
The reflector is always slightly less than the leading light. To soften it more, just use white rather than silver. If you want to warm it up, use a gold reflector.
You want the leading light up about 45º above the camera lens and straight above it. This will make the light hitting the face come down across it, help those cheekbones pop, and give some contours to the front. Straight on to the model will kill those cheekbones and flatten out their features.
By the way, I also like to use a tripod to glance above the camera to keep a personal connection with the people.