Killer Instincts:  Zachary Quinto of Heroes

In truth, we kind of liked it better when we didn't see Sylar, and the character's presence was felt mostly off-screen and in shadow as a super-powered serial killer ripping people's heads open, a fresh take on the modern supervillain. 

Then Zachary Quinto happened.  And then the rest of Heroes happened.  And then the cancellation happened.