Challenge:
Choose your favourite serial/episode from each of the Doctors eras. Only TV serials/episodes for now. Sorry McGann!
First: The Sensorites - really cool serial and it's the one where the First gets that bitchin' cape.
Second: The Mind Robber - I was feeling the mindfuckery of this story as an adult in 2015. I can only imagine how mind bending this must've been for the kiddies in the 60's!
Third: ...I have to admit, I just don't really care for many of the Third's adventures. Probably something with The Master in it? Colony in Space maybe? I dunno, whatever.
Fourth: Androids of Tara - This is a weird choice, I admit, but I'm a sucker for worlds that seem superficially like some past human era, but actually have incredible technology in certain ways. Also, in my head canon, the fourth doctor learned to fence in the middle of his duel with the bad guy at the end. He goes from terrible at the beginning to learning at such an incredible speed that the bad guy just can't keep up by the conclusion of the duel, ending with the Doctor smugly remarking, "Was he supposed to be good?" when the locals are astonished that he vanquished such an accomplished swordsman.
Fifth: Caves of Androzani - I hate to pick the one people always choose, but it really is the best. Also, I showed his regeneration scene to my mom and she said that she kind of hated Davison purely on the basis of his replacing her favorite Doctor, but even she really didn't want him to go when she saw his regeneration. Hats off, Davison. You did good.
Sixth: Vengeance on Varos - Not a lot of good choices for the Sixth. I liked some of the scenes where the doctor is fighting off hallucinations in this one though. *shrug*
Seventh: Easy, The Curse of Fenric - It's got alien vampires, elder gods returned for revenge against a Doctor who already outsmarted him once before, one of the first examples I can think of where the Doctor has to trick the companion into thinking he doesn't care about her in order to win. And Explosions (thanks, Ace.) It's a good one.
Eighth: Night of the Doctor - So good it gets the shout out, even though it's a short...and also his best Big Finish is Chimes of Midnight. Just saying!
Ninth: The Empty Child/The Doctor Dances - Probably the only story I liked in series one of the new stuff. The idea of a woman being patiently stalked by a monster through London during the Blitz is just too good an idea and, at least this time, "EVERYBODY LIVES!" felt earned.
Tenth: Silence in the Library/Forest of the Dead - If I'd been asked a few months back, I would've said Girl in the Fireplace, but having watched this two-parter again I remembered just how crushing this story is and how scary. I'm talking specifically about Donna's half of the adventure. Holy shit, so amazing. The stuff with the Doctor and River is Ok too. The references she makes to actual adventures that happen with the 11th is kind of neat in retrospect.
Eleventh: The Pandorica Opens/Big Bang - This is probably my favorite season finale of anything ever, the end. It was so quintessentially the Eleventh Doctor: big, loud, silly, impossible and also kind of magical in a way I can't put my finger on. I love this story. All the Geronimos throughout the season feel like they're building to the one he sends back as he rushes headlong towards certain doom near the end of The Big Bang.
Twelfth: Mummy on the Orient Express - This might be my current favorite single episode. I love the setup, I love the locked room mystery aspect of it. I love the little countdown timer whenever the monster is on screen. I love how the Doctor solves the problem, I love the speech he gives during the very last scene of the episode. Capaldi is magnificent in it, Jenna Coleman is magnificent in it. The sadness of a last great adventure adds a cool melancholy to the whole episode. This is probably the episode I'd show new people to convince them the show was worth giving a shot now (not that this is usually a problem anymore.)