The pose, composition and main light are all great. As mentioned, his hair & shirt are getting lost in the background. A background light and/or a hairlight kicker would help to set him apart.
Focus isn't good either... but I agree with the above comments about contrast... the flash also causing some poor reflections, which are probably more noticable on a bigger version, on the earing and ring...
the problem i'm having is my flash giving too much light, so i covered it a little for these. I'm still not happy with my whole lighting situation though.