I like to keep portrait lighting simple. Very simple. For example, for this portrait, inspired by Vermeer's paining, Girl With a Pearl Earring, I used only one Canon Speedlite in a Westcott Apollo soft box.
I used that softbox because it has a recessed front panel that lets me (and you) direct the light and shape the light on the subject.
I used the black side of a Westcott light modifier to darken the shadow on the shadow side of the model's face.
Careful lighting made the subject stand out from the black background.
My friends at Adorama have put together a cool speedlite accessory kit at a cool price that you can use to make dramatic portraits in the comfort of your own home - and on location. It includes the softbox, light modifiers and light modifier stand that I used - plus a sturdy background stand and larger background (which is way better than the piece of black material that I pined to my bookshelf. Just add your speedlite.
Here are two quick portrait tips: One - If you want an interesting portrait, don't light the entire face. Two - Keep in mind that the camera looks both ways. When you are shooting, know that the mood, energy and feeling that you project will be reflected in your subject's face - and eyes.
Above: See, you don't need a pro studio to get professional looking portrait. I took my Girl with a Pearl Earring image in my home office.
Here's a quick tip on all lighting: Shadows are the soul of the photograph.
Explore the light,
Rick