Ever since the current Doctor Who series began airing in the States and gaining in popularity, I've had people approach me saying they were interested in exploring the original series and ask where they should start. Enough people that I started making lists. Enough, in fact, that I ended up making one big list that I saved as Google Drive and Evernote docs so I could just send it out to any new people that asked rather than have to recreate the thing from scratch every single time.
After getting their assurances that, yes, they knew what they were in for and that their imaginations would have to fill in a lot of the things that are being taken care of by the special effects budget nowadays (I've heard people compare classic Who to filmed plays rather than "typical" TV programs, and I think this is often spot-on, particularly in the early days), I send them my recommendations for the stories I think they should watch. I always include the caveats that these are my recommendations, that their tastes may differ, and that I include a few widely-accepted-to-be-bad stories in the mix because they may still be technically important to the show's history and/or I just happen to like them in spite of their shortcomings.
I've expanded the list a bit for bloggy purposes, but the same caveats apply. These are my recommendations, yours may vary wildly, and there's a bit of bad in here because if you want the full classic series experience, you need to experience a few groaners, in much the same way everyone interested in Star Trek needs to see Spock's Brain or the one with Space-braham Lincoln.
I've also only included stories known to be complete (or mostly complete) and available commercially on DVD/VHS because it's just easier that way. If someone wants to experience the (sadly many) lost stories through recreations or on CD, they can explore those avenues on their own.
Classic Series Starting Point: The Five Doctors. No question at all.
Although it has its flaws (the original first Doctor had long since died and was replaced by another actor, Tom Baker opted out and is replaced with un-aired footage, Sarah Jane falls to her near-death down an ever-so-slight incline, certain story beats don't jibe well with series continuity, etc.), this 20th anniversary story is the best starting point because you get a feel for the then-current Doctor and each of his predecessors, various companions and monsters, and some costume-drama-esque palace intrigue besides. It's a Whitman's Sampler for the entire series up to that point, and a great way to lead you off into other eras if you want to learn more about, say, this Pertwee fellow with the cloak and the yellow roadster. I'm also partial because this was one of the earliest stories I ever saw, and it went a long way toward explaining to 8 or 9-year old me how this was a show about all these guys who were really just the one guy.
Moving on by Doctor (not necessarily the order I think everyone should go, by the way, but certainly the easiest way to list everything)...
1st Doctor – William Hartnell
- An Unearthly Child (also called 100,000 BC or The Tribe of Gum) – The very first story, and unarguably one of the most important. It introduces us to the characters and the concepts (establishing the alien natures of the Doctor and his first companion, his granddaughter Susan, right out of the gate), and sets the entire series in motion. Unfortunately, the three episodes of the serial that follow the first episode (from which the serial gets its now-accepted name) are pretty boring (the Doctor and company get trapped, escape, and get trapped again an awful lot), so don't feel bad if you skim those in fast forward or skip them completely, but that very first episode is a must.
- The Daleks (also called The Mutants or The Dead Planet) – First appearance of the show's most famous villains (whose popularity rivals or may even top the Doctor himself), the titular Daleks. At 7 episodes, I think it goes on too long (a frequent complaint about the black and white era), and a lot of the backstory established here gets contradicted later, but again, it's important to the show's mythos and there are a number of effectively chilling bits that help explain why so many Brits grew up watching this show while hiding behind their sofas.
- The Edge of Destruction (also called Inside the Spaceship) - After cavemen and Daleks, the cast get a "bottle episode" story taking place entirely within the TARDIS. Things get a little surreal, but it's a great chance to get inside everyone's heads.
- The Aztecs – In the early going, the series would switch narrative focus between serials, alternating between a sci-fi story and a straight historical adventure (which often had few or no SF touches at all besides the whole time travel thing). This story is one of the earliest of the historicals, and often cited as one of the best. It's also the earliest example of the series's back-and-forth philosophy about whether or not you should directly attempt to change the course of history.
- The Dalek Invasion of Earth – Once again, a few episodes too long, but this really establishes the Daleks as the series's one, true Big Bad (they don't just invade Earth, they have already conquered it by the time the story begins!). It also features the first time we see a companion depart the series, leading to Hartnell's brief, wonderful monologue that kicks off The Five Doctors.
- The Chase – The Daleks get their own time machine and chase the TARDIS all over creation. Lots and lots of fluff here, just packed to the brim with tons of silly and episodic padding (and a blatant attempt to recreate the Daleks' success that just falls flat), but I think it's fun.
- The Time Meddler – The first important story for the show's mythology (and what little we ever get on the Doctor's backstory) since the very first one because we finally meet another member of the Doctor's race, himself an on-the-run renegade. We're still a ways from hearing the words Time Lord thrown around, but we get our first look at another TARDIS and get confirmation that the Doctor's is an older (and quirkier) model. We also get more talk about just how involved a time traveler should be in the flow of history.
- The Tenth Planet – Important for two reasons. First, we're introduced to the Cybermen (my favorite Who monster), who may look like body-stocking wearing accordion-fetishists here but they end up being twice as creepy as a result (the early Cyber-voices add to the effect). Second, and more importantly, it's Hartnell's final story. He doesn't get a lot to do throughout the story (his health was failing in real life), and at its end we find out why, as his body gives out and we find ourselves saying goodbye to one Doctor and hello to another for the very first time. The final episode is one of the many that are lost, but the regeneration scene still exists, and this is being released on DVD in the coming months with the complete final episode being replaced by an animated stand-in.
2nd Doctor – Patrick Troughton(Frustratingly, most Troughton stories (and a sizable chunk of Hartnell's, for that matter) no longer exist in complete forms. Stupid BBC and the short-sighted archiving policies of early television in general! You can see sample episodes from some of those - the Lost in Time box set has a bunch of loose ends from both Hartnell and Troughton - but here’s what’s worth watching in more-or-less complete form.)
- The Tomb of the Cybermen – The best Cybermen story ever. A lot of early Who, Troughton's era in particular, consists of "base under siege" stories, but Tomb is unique in that rather than something trying to break in, the cast is trapped inside with the monsters. It's a little bit sci-fi, a little bit Hammer horror. Some nice Doctor/companion moments, too, particular with then-new crewmember Victoria. You'll have to overlook some painful sexist dialogue and badly stereotyped Americans, though.
- The Mind Robber – The Doctor and companions are taken to a land where fiction becomes reality, and a creepy place it is, too. For once, the thriftiness of the production actually becomes a strength rather than a hindrance because it helps lend to the surreal qualities of the setting and the story. Also contains a very clever way to write out an ill castmember for an episode and Wendy Padbury in a spangly catsuit.
- The Invasion – Another great Troughton-era Cybermen story, one that's officially incomplete but missing bits were filled in with narration on VHS release and full animation on DVD. Fun for the character beats, scenery chewing human villain, bizarre fashions, and lots of great shots of Cybermen stomping through 60s London. Important to the series because it contains the second appearance of recurring character Brigadier Allistair Gordon Lethbridge-Stuart and the very first appearance of UNIT, an organization of questionable secrecy that defends the Earth from various threats and becomes very important in the Pertwee era.
- The Seeds of Death - Feels a bit padded, but I think the Ice Warriors are fun villains, the story has a nice message about the continued value of some technologies (and people) society declares obsolete, and Troughton really does his best to sell a giant pile of soap suds as a threat.
- The War Games – At 10 episodes, I've always thought Troughton's final story was WAY too long, but the penultimate episode of the story features a problem too big for the Doctor to solve on his own so he has to call in the help of the Time Lords, and the series would never be the same. We don't get a lot of backstory, but we get a little more about the Doctor's origins and a lot more about his motivations. Even if you skip most of the rest of the story, watch the last two parts, especially for Troughton's memorably unusual exit.