As far I know, James Marsters was never on HEROES. (I think maybe someone is confusing him with that blond British actor who played Hiro's immortal nemesis. You know, the guy from ALIAS.)
And:
Christopher Lee
Count Dracula (umpteen Hammer movies)
Saruman (THE LORD OF THE RINGS)
Count Dooku (STAR WARS)
Peter Cushing
Dr. Frankenstein (several Hammer films)
Dr. Van Helsing (ditto)
Sherlock Holmes (movies and tv)
And:
Christopher Lee
Count Dracula (umpteen Hammer movies)
Saruman (THE LORD OF THE RINGS)
Count Dooku (STAR WARS)
Peter Cushing
Dr. Frankenstein (several Hammer films)
Dr. Van Helsing (ditto)
Sherlock Holmes (movies and tv)