Since I've been asked by two people... I've watched about six or eight episodes of the Sopranos early on, but I don't get HBO or those channels, and really don't watch much TV or DVDs unless I'm down with a cold or something. I'll lay out the parameters and you guys can take it from there.
Personality Disorders are not all-or-nothing. By definition it's a pervasive social and mental 'style' that shapes most of what the person does to some extent, and is somehow maladaptive (in the big social picture). People can be really really severely disordered, or just moderately but still enough to fit the definition.
People also can have strong traits or 'features' but be flexible or socially skilled and adaptable enough that it doesn't fit the diagnostic level. For ex, a great many corporate and political leaders are very narcissistic, but it's actually sort of adaptive and they have the ability to ratchet it back if necessary. Many research scientists and CPAs have obsessive-compulsive personality features, but not so much that it's a problem. Cops, commandos, and psychologists all score very high on sociopathic traits - for different reasons, but it is actually professionally adaptive and beneficial. btw, technically it's Antisocial Personality Disorder, because 'sociopath' now connotes extreme criminal behavior, but we still use 'sociopathy' to describe it.
So it's not accurate to say antisocial personality can only be the most extreme form. Sociopaths are not all completely without conscience, but they are more likely to rationalize it as 'self defense' behavior (He would have cheated me if I hadn't outsmarted him) or just disregard it as personally inconvenient and not a big deal. They are almost reflexively oppositional to standard authority and social norms.
They can't stand being bored, and impulsively act out or take risks to get a charge. The most severe cases -- psychopathic serial murderers -- only show activation of brain pleasure centers with that kind of extreme risk, and show almost no activation of social frontal lobe centers when asked to watch and evaluate criminal, even murderous, scenarios. Most sociopaths do show activation, but less than the average person.
Sociopaths also tend not feel anxiety as much as normals and they will tend to get mean and aggressive in response to circumstances where normal people would feel uncertainty or anxiety. Sociopaths (at least jailed ones) seem to learn cause-and-effect only from immediate, severe non-social consequences, where other people learn from approval/disapproval given socially.
They don't lack empathy -- the ability to really understand and feel another person's feelings and state of mind -- because empathy misused is precisely what makes them great cons and manipulators. They tend not to ever trust anyone at all, and they don't bond easily in terms of emotional intimacy -- they may or may not want intimacy, but almost all antisocial types feel deeply alienated and permanently set apart. In severe cases they turn other people into mere objects.
They may have some strong personal values -- which could be very idiosyncratic, but for ex, a child rapist who goes to prison is not going to survive, because even the hardest sociopaths can imagine their kid in those circumstances. So if they like a particular person for whatever reason, they could protect him.
So Tony Soprano? He's definitely got sociopathic qualities (doesn't matter if he had a lousy childhood -- behaviors are behaviors), and he's certainly narcissistic (he enjoys the attention of studying himself in therapy and expects to be the star patient -- the ONLY patient), but as I recall he was too anxious to be a real sociopathic personality disorder. Not everyone in therapy fits a diagnosis, you know. Sometimes they're just chronically unhappy or ineffective.
