Angel(1999 - 2004)
Angel, a vampire with a soul, left Buffy and Sunnydale behind after deciding that it wasn't safe for him to stay around those he loved and cared about.
He moved to LA to battle evil wherever he finds it, with the help of visions from the Powers That Be through Doyle, a half-demon Irishman, and later Cordelia Chase, a longtime friend of Angel's from Sunnydale, who's adamant that her work for Angel is just until her acting career takes off.
With infrequent appearences from Spike, Buffy, and other characters from the original series, Angel is one of the most successful spin-offs of recent times.
Season 1 (Glenn Quinn in credits)
Season 1 (Alexis Denisof in credits)