The key to that shot is using the light to isolate the subject. To achieve that you must restrict the light from hitting the background. Here is the best set up shot I have from that shoot:
Unfortunately you cannot see the flash in that shot (a Nikon SB600 with a radio trigger), it was on a light stand high and just outside the left side of the frame. You can however see that I used a piece of plexiglass suspended between two chairs with a large black cloth suspended behind. By using the plexiglass instead of an opaque background I could make sure that the only thing being lit by the flash was the subject. Only a little post processing was necessary to remove a couple scratches and smudges in the plexiglass.
I also restricted the beam of the flash using a grid spot to keep any light from splashing onto the background. Here is another example of the flash with the grid spot in another shoot:
As you can see, the beam is much more narrow than usual. That setup was used for this shot:
The last thing needed to make a nice solid black background is to use a relatively high shutter speed to that none of the ambient light makes it into the shot and the flash provides the only light. In fact, in the crestie shot I did not use a background at all, I just dimmed the lights in the room and used a shutter speed around 1/250.
Sorry this ended up so long-winded and technical, I'll be happy to provide any clarification if anyone needs.