Wow, harsh Pertwee and Davison...
I think Davison's era had some really good stories ("Kinda" probably being my favorite) and he has the best regeneration by a mile, but I've always seen him as a little dull compared to the other Doctors. He comes off as a very Default Doctor. His most stand-out trait is that he's a big cricket fan. That doesn't draw me in like the sillier, more cryptic, nihilistic, or romantic Doctors.
I really like Pertwee, but I just happen to like everyone I listed before him more. Yes, even Colin. He got a major boost from the audios, along with McGann.
Personally I've never fully understood the love that the 9th Doctor gets in here.
He was okay (for the one season) but was he really THAT good?
If 11 was the Doctor for only one season would you hold him higher regard than what you do for him now? You know, the old less is more scenario.
IMO, 9 was the "least" Doctory of them all.
Costume, accent, personality.
Well, for me it's--
I think it helps that 9 had a complete arc that was well planned out from start (war beatten with a death wish) to a very nice end (found something worth living for again).
--basically what Valumart said. Eccleston's Doctor had a great character arc. He was a broken man, but there were glimpses of a more jovial man tucked away inside. Plus he was my first Doctor, and I went in there without any expectations on what the Doctor should be like; he won me over as a tragic hero in a television series that was completely new to me.
With 10 they kinda just faltered around a lot and threw things at you.
Even worse, he had a character arc that was about him becoming a hypocritical, vengeful madman with a god complex. He punished others for doing things he himself would've done (see: chewing out his own clone for killing the Daleks. You can't blame the Donna side of him for that, because
Donna was right there and the thought never crossed her mind), and his stance against weapons bordered on the ridiculous (stopping Jack from firing at a pack of man-eating predators, yelling at a UNIT colonel who had been nothing but polite til that point). And in the end, when it was time to die, he guilt tripped Wilfred before finally saving his life. The bastard.