Tom Baker was my first, and will likely remain my best.
Which part are you having trouble with?
Big Tom Baker fan, but Tennant had more depth (as does the revival). It’s comparing apples to bowling balls, though.
BTW, you left out Peter Cushing and Richard Hurndale. 
While I grew up with the show, Tennant is my favourite. I think Matt Smith is doing a wonderful job, and I certainly have no complaints about him, but Tennant edges him out for me.
It’s hard to compare them to the older Doctors because - to me - it’s almost a different show. If the older Doctors had the show format we have today, I imagine they’d have come across very differently. There is much more emphasis on character these days, and the newer Doctors benefit from that fact.
altho i adore tennant, eccleston’s bad boy in leather act does it for me (why yes, there IS a theme going on for the queen today regarding doctors wearing leather :p).
i’d never seen the doctor so dark and complicated and REAL before and was instantly hooked on nu who as a result.
I liked Jon Pertwee. Sadly they had a lot of budget cuts and many of his episodes were stuck on earth. He couldn’t travel in the Tardis for awhile.
New Who - probably Eccleston he only did one fantastic season. I will always wonder if he could have kept that high standard after several seasons.
I haven’t seen the old-Who, but I like Matt Smith the best of the new ones. With the budget, time constraints, and overall atmosphere of the show, I simply can’t take it all that serious. The scary monsters aren’t scary, they’re just a whimsical show’s take on scary monsters. Smith works in this setting. Tenant did as well, but not as much.
I think you may have missed the subtleties of Smith’s acting. It’s fairly obvious that he gets a lot of what is going on around him and is specifically acting more out-of-it than he actually is to push things in the direction he wants. For example, he’s aware of Amy’s fondness for him but pretends not to, to drive her away.
I’ll grant that he doesn’t have growth as a character, but at 900 years old or whatever, he’s already grown as much as he can. The hard part for him, which Smith gets over, is figuring out how to still be able to interact with people who are so much younger and inexperienced. If he acted serious, he’d just end up sounding like a cranky old man yelling at kids on his lawn, “What the hell are you two kids doing, running out alone on an alien spaceship!?” Either that, or if he’s just completely awesome in all ways at all times, everyone around him would feel a bit small. Acting like an idiot allows him to seem like their equal, to balance out the awesome.
I definitely think David Tenent was the best. Of course, I feel a bit put out that he didn’t stick it through a few more seasons, but that’s life as n actor I guess. I think Christopher Eccelston would have been way up there, but it is very hard to compare on just one season. I do wish that he had more time as the doctor. Matt Smith is doing a grand job, but following David Tenant is not easy.
I watched one Tom Baker series and I don’t care for it. As a doctor, he may have been fine. That series was boring.
Tom Baker introduced me to the character. He still is the actor that I compare all of the others to. He will always be my favorite, although Tennant was close.
They say you never forget your first Doctor, and Tennant was mine. Matt Smith is definately growing on me though.
Matt Smith is a very good Doctor, as was Tennant, but they both suffer in my eyes because I very much dislike the direction the show took under their tenures. Tennant also was too reliant on very few expressions and poses and by the end his Doctor was bit too much like a collection of ticks. It’s a pity, because Tennant most certainly could act when he had the material and the desire to do so. Smith would rank very high with me were it not for the producer but David Tennant is closer to the bottom of my list, near Peter Davison.
My favorite Doctor was probably Tom Baker, despite his excesses during the middle part of his era. He may not have been as nuanced as Smith in his performance, but he more than made up for it with power and charm. Colin Baker would have been in the running as well if the audios were more well-known, but I don’t think it’s right to nominate him based on stories relatively few people know and told in a format so different from the rest of the show. Pertwee I love dearly, but I recognize he’s a bit too limited to rank high. This whole thing is very hard because I honestly like them all so much.
Tom Baker is MY Doctor, but he still comes in second to Tennant, who just WAS the Doctor.
ETA: I found out today that the favorite drive-in movie series of my childhood, the Harryhausen Sinbad films, have TWO Who connections: Tom Baker played the evil magician in The Golden Voyage of Sinbad and Patrick Troughton played a Greek alchemist in Sinbad and the Eye of the Tiger.
I’ve only watched the new series-es, so obviously my answer (Tennant) is very incomplete. That said, of the new doctors, I feel Tennant acts the part the best, but Smith has much better writing to work with.
It wouldn’t be the first time I missed something subtle but in this case I think the fact that you read what is going on how you do is exactly the point I am making. To my read you’ve been missing some of subtleties of the writing. His anger comes off as almost all postured, but it shouldn’t.
The Nu-Who Doctor has been going through tremendous character development. We joined him as he was dealing with the pain of having dealt with The Time Wars. Last of his kind now and by his hand. Afraid to let himself care or even attach to anyone. It was by way of Rose that he, during Eccelston’s short tenure, realized he needs people around him and that he completely adopts humanity as his family. Tenant’s reign brought us a Doctor continuing to deal with his loneliness, and with his place in the Universe. Do the old rules still apply? How powerful is he? And at points starting to go past the usual Doctor arrogance and bravado and acting more like a god … and having his wings clipped sometimes when he does. “Midnight” also showed him how limited his power can be without the help of his companions. The writing for Smith’s Doctor also has him dealing with his being clipped some and dealing with losses yet again and very real anger in addition to postured anger. Is he too powerful?
This is great grist and he does okay with it, but the anger part he could do better.
I voted for Tom Baker because he’s the Doctor I grew up with. I actually quite like the new Doctor, Matt Smith. He’s darker and more tortured and I love his current sidekicks Rory and Amy. I tried to like David Tenant but he just didn’t do it for me.
Much as I agree with the praise for Smith, I went for Tom Baker as he’s the definitive Doctor in my mind, goofy stories notwithstanding.
By the way, I occasionally ponder the fact that there’s nothing to stop the DW franchise from bringing back McGann to fill in some Eight episodes. We never saw him regenerate so he could have got up to all sorts of things.