It's Matt Damon.
But does this mean the previous "Sexiest Man Alive" is now obligated to die? Are previous years' "winners" either no longer sexy or no longer alive? I remember when it was Matthew McConaughey. Last I checked he was both still A) alive and 2) sexy.
Perhaps each year People should either deem the previous recipient of the title still the "sexiest" or kill him. All for the purpose of clarity, of course. After all, our culture will survive without another McConaughey movie and, unless he's waiting for me in my bed tonight, I won't miss him.