I like this. I agree that the first crop would be great for placing text in the negative space, but as a standalone image the square crop works better for me. In general I like images which push the conventional limits of negative space as in your first crop, but with such a tight zoom on the face the extra negative space seems incongruous to me.
You've clearly put a lot of though into the lighting so I'm guessing this is the effect you were going for. Just my personal preference, but with this subject and the black background I would like to see this with more shadowy, moody lighting.
You said this is a setup shot for something you're trying to recreate - is this the final subject? I only ask because the blue earring bugs me a bit. I like the little bit of color in the image, it's just that because it catches the light a bit it draws my eye there, to an area which is out of focus. You might want to consider either a less catchy earring (for instance a matte colored stud) or a different depth of focus to bring that area more into focus. I wouldn't necessarily change it (I like the degree by which the hair behind the ear is out of focus), just something to think about.
Lastly, his forehead is just a bit shiny from natural oils. Since guys aren't as likely to submit to makeup to dull that shine I keep paper towels handy so he can give a quick wipe of the T-zone. It's not too shiny here, just something else to keep in mind.