Portrait Lighting Setup poster to be helpful. It contains 24 different portrait lighting setups using a variety of lighting gear and lighting patterns. Click the image to see it up large. Also check out some of the further reading.
This beautiful Rembrandt portrait is lit with a soft one light source with vignette background. I was drawn to this image because of its innocent painter like style. Photograph Ksenia by Paul Apal'kin on 500px