Well, theoretically, to get them to swing open properly without binding, the axis of rotation for each hinge has to be in line (translation: in-line and perpendicular to the front side). There may be enough slop in the hinges to allow you to mount them without the axis of rotation (meaning, the line drawn through the hinge pins) exactly in line if it's displeasing to the eye.
This is completely unrelated to the axis of evil in which case you can do anything you want apparently.