Like them all, but I think I like the one with his big old open smile the best.
My rottys see the camera and they get all serious and won't smile. One won't even move. He doesn't seem afraid, but rather seems to know to sit still and pose. (very odd)

Only distraction I see on that one is the white spec of dust (or doggie treat?) on his forehead.

I would have to agree that the folds in most of the photos add depth and leading lines, but on that first one the dark crease leading straight off to the right could use softening or removal.