Will the Real Sociopath Please Stand Up?

Sociopath, psychopath, person with anti-social personality disorder diagnosis...it isn't a simple task to find agreement about these descriptions. Are they synonymous or distinct from one another?

Aside from the individual who as a child was "fascinated by fire" and actually started fires, tortured small animals then graduated to a sadistic serial killer of their fellow human, do any of these terms describe someone who is basically bereft of a conscience or failed to physiologically develop whatever part of the brain that provides the ability to empathize or feel guilt when it would be appropriate? That's the person I'd like to understand better.

To that end, here is short "favorites" list (mine) of links that provide different perspectives on the subject:

Profile of the Sociopath
The Unburdened Mind
Sociopath World

"How You Feel What Another Body Feels"  
Scientific American, (Article) June 26, 2012
"How to spot a sociopath"
Natural News, (Article) June 8, 2012