4. 1st Doctor (William Hartnell)
Best Serial: The Time Meddler (Season 2, Serial 9)
Worst Serial: Planet of the Giants (Season 2, Serial 1)
The Doctor. The original, you might say. Full disclosure, I initially went into my rewatch with a favorable view of Hartnell's Doctor because a girl I liked was obsessed with him and had him ranked as her favorite, and my response was "Oh yeah, he's great! I like him too!" However, William Hartnell does stand on his own two feet as a great character in his time as the Doctor. I'm a big fan of the Doctor in general being played like a grumpy old man who does not have time for the bullshit that he's forced to deal with. You can see that in that arguably all four of my top four fit this description in some capacity.
During Hartnell's run, he just had this delightful aura of being above it all. He's an old man (or at least looked the part), and he's largely not going to go around getting into fights, or running from bad guys...so he lets his companions handle those responsibilities while he wanders around and explores and investigates. Also, he killed a guy with a shovel one time, which is hilarious in and of itself. But yeah, just the level of irritated snark and wit Hartnell's Doctor displays made for a real fun watch with him at the helm. He was absolutely the STAR in the role, and while Tom Baker was able to portray the Doctor as traditionally alien, Hartnell definitely gives of that aura with a more subtle touch. He's very detached, and he's very knowledgeable (given that his role in those early seasons was to be a teacher on an educational program), but he does it in a way that goes behind just a wise old grandpa.
Ultimately though, he comes in fourth because I have to agree somewhat with what Ryo said. Hartnell's Doctor feels so completely different from everything that came after, because he wasn't just going around and saving the day. Hartnell's Doctor largely just traveled around and checked out things that interested him. Sometimes he'd face a major enemy like the Daleks, but other times he'd wander around Rome, or China, or the Aztec civilization, just having fun and exploring. Don't get me wrong; that attitude is very well-suited for a children's program, but he's not the kind of savior or hero that we got from later versions of the Doctor, and I think you kind of need that in order to really understand the Doctor as an overall character. It's funny that Hartnell is so old, because it feels like regeneration into younger actors is what gives the Doctor's character the wisdom needed to become the person they are today.
Hint for #3: One of only three numbered Doctors who didn't last three seasons in the role.
Touch fuzzy. Get fuzzier.
Inviso