In 1963, the first episode of an untried series broadcast on the BBC, it was Doctor Who and has since gone on to be the longest running science fiction show in the world (no doubt helped by the plot element of regeneration).
I have been a fan since 1977 and Tom Baker remains my Doctor, but to one extend or another, I have enjoyed all of the Doctors. But I think Davidson, McGann (who could have been amazing) and Tennant, round out my absolute favorites.
While I was a huge Whovian, even being part of the small Doctor Who cosplay group for the 2nd Dragon*Con parade, my love of the show has cooled in recent years. Not much of a fan of the direction that Moffatt has taken the show but I do still watch, it is just no longer a central part of my Fannish Identity. Though I suspect I will be a fan til my chance to regenerate comes up.
There is an interesting bit from the BBC here about how the actual creation of the character and the name come about remains a mystery, quite amusing and appropriate.