I like the detail in this, as well as the inclusion of the shirt collar (for some strange reason). Your skin looks a little odd, colour-wise. Just a thought - did you use Lucis on this?
I like this one, but the crop bothers me a bit. My eye keeps going to the upper right corner and thinking that you have a really big head. On the other hand it's a great pose and does show a lot of emotion.
This strikes me deep. I think because of the lighting and the pose. A strong sense of reflection and contemplation is conveyed quite well here. One thing you might want to think about is cropping off some more on the right because I think the pose makes your head look awkward or has an abnormal shape. Unless your head really is shaped this way and I've just insulted you :P
All three are done well, especially the edge highlighting (moreso on the others), and the processing, which complements them very well. It's actually difficult for me to tell when you're serious and when you're not -- that's probably a good thing -- but taken at face value, they're doing a pretty good job of emoting. My favourite is this in that department, being more understated, with the close crop showing off a lot of great texture and colour that's interesting to look at.