I am a Whovian. Having tuned in regularly to Doctor Who since his re-incarnation in 2005 through to the present day and stumbled across many "older doctor" episodes I would like to think I have sufficient knowledge to make a valid decision.
David Tennant was my favourite doctor. Recently he was also voted the nation's favourite Doctor by the Radio Times readership alongside his best companion, Rose Tyler (Billie Piper) and in 2007 his Doctor was named "the coolest character on UK television" . He brought his own twist to the role of the Doctor, after the slightly more serious spin that Christopher Eccleston put on the role; Tennant's Doctor was refreshingly light-hearted but he also had a darker side which was less apparent in other Doctors.
David Tennant had been primed for the role since he was a young boy, a self-proclaimed Doctor Who fanboy. Tennant first put his name to the Doctor Who franchise in 2003 when he took part in a Doctor Who animated webcast entitled the "Scream of Shalka". Tennant was not originally cast for the role, rather he was involved in a production that was taking place in a studio next door but when he discovered what the BBC were up to he sweet-talked his way into the director's heart and landed himself a role as a caretaker. Tennant, still keen to be associated with Doctor Who, took part in a series of small plays which were based on the idea of Doctor Who, although Tennant still hadn't clinched the role of the Doctor in these early days. There were many other Doctor Who-related audio appearances for Tennant before the tenth Doctor came into his own, having been overlooked to play the ninth doctor (although he was definitely considered for it by the BBC). For the Scot, being the Doctor was a childhood dream and he is still as enthusiastic about the series now as he was back then.
If the fact that he has abundant enthusiasm for the show was not enough, then one could point to his wonderful acting skills which meant that he could have played the Doctor with ease without having any previous knowledge of the role. Frequently nominated for "Best Actor" awards (and not just for Doctor Who) no-one can argue that Tennant's acting is anything but exemplary and this is shown in his ability to sustain the same character so well throughout every episode that he was involved in. The speed of his babbles were quite amazing and he was able to represent the Doctor's brain speed consistently because he was so fluent with his lines. For me, the babbles are possibly the most memorable aspect of Tennant's Doctor; he would seem to lose himself in his thoughts as he solved the problems that were presented to him and the odd words that the viewer would hear made for an interesting string of words which (for our ordinary human brains) were hard to link together.
It was not just confusing for us as viewers but also for his companions (of whom I think he also had the best), who had to try to keep up with his fast pace. Rose Tyler is the most obvious companion who comes to mind; although she originally was the Ninth Doctor's companion, the chemistry between her and Tennant was a lot better. Then there was Martha, who was not one of my favourites as I found her backstory rather lacking, but when we came to Donna Noble (Catherine Tate) I immediately loved her. Tate's complete lack of knowledge about the Whovian world did not detract from her character; it almost helped her portray her character's amazement on their travels. Noble and Ten were the funniest combination in my opinion, great writing, as well as Tate's natural comic ability, made for fantastic chemistry rivalled only perhaps by Amy and Eleven.
Obviously without Eccleston's base to build on, Tennant would not have thrived and I would accept that Eccleston was the right choice for the Doctor's revival, but he lacked the spark and twinkle of Tennant which made his episodes slower and, in some cases, less exciting. On the other hand ,Matt Smith does have the speed and wit which is very similar to Tennant , but his serious acting leaves more to be desired and for me it is slightly less heartfelt when Smith is serious. His Doctor is naturally happy and I almost miss the darker element to the show, although I do enjoy his slightly more childish approach to the Doctor.
I am unbelievably excited for tomorrow. It will be the first time Tennant has played the Doctor in three years - I cannot wait to see him back in his most iconic role and I'm particularly interested in how the Tenth and Eleventh Doctor will interact on screen. Fulfilling his final wishes in 2010, he didn't want to go and now he's coming back.
It promises to be a very special episode.
See Tim Bustin's profile of the Ninth Doctor (Christopher Eccleston) and Ruth Richmond's profile of
the Fourth Doctor (Tom Baker); Mark Richardson sees parallels between the Doctor and JFK.