Showbiz

An originally not too succesful 1970's TV series (it has reached cult status since, and episodes have been shown somewhere in the world on every day since the first rerun until today ) saw two reunion TV movies in the '80s.
The series was broadcast on ABC, the first reunion movie on NBC and the second reunion movie on CBS, resulting in a rare feat: air time on all of the "big 3" networks.

What series was this? And for bonus points, who was my favourite character?