I'm sure that many people would be attracted to the model's nudity (and she is very beautiful), but what 'sells' this for me is her facial expression... it elevates it above the 'just another nude portrait' type of photo. Hats off to both the model and the photographer! (Great natural lighting, by the way!)
Good lighting, minimal shine from the skin. Facial expression is spot on. Good color for skin for a shot like this, compliments the lighting nicely. With a little professionalism, I can see this on the cover of something expensive.