That was often a question mooted for presentations back when I was at school and never being one for the cult of Celebrity I usually had to have a big think about. My usual choices were the actor Patrick Troughton, who was a prolific character actor from the 50s up until his death in 1987 who had memorable roles in The Omen, The Scars of Dracula, Just the Two of Us, the Box of Delights but probably most famous for being the second Doctor Who.
At the time I usually made a point of him being a versatile actor who shunned the star focus but now with the recent biography written by his son it becomes apparent that this was partially due to the double life he was leading. In short he had two families but for the public he was a happily married man, a set up which could not happen today with our constant gutter press and paparazzi persecuting every one in the public eye. Quite how he did it don’t know, I find it hard just to keep one girlfriend let alone two families!
Another one I would mention would be the writer Terry Nation, the man who created the Daleks, Blake’s 7 and Survivors. He was script editor on the final season of the Avengers and contributed scripts to all manner of shows including The Saint and the Persuaders. Now it is fashionable to mock Terry Nation as he often writes very pulpy stories but they are always entertaining, if they were books they’d be called page turners. True he did get a bit lazy and recycle material (or in one case an entire script) but when pushed he created masterpieces like Genesis of the Daleks, Blake’s 7: The Way Back, Space Fall, Dual and Terminal and pretty much all of his scripts for Survivors are excellent and very much against his usually fare.
I strongly recommend the biographies of both of these gents.