An Unearthly Child is of course where it all begins. The first episode, where the teachers Ian and Barbara follow the mysterious pupil Susan home and discover that her grandfather's police box has an unexpectedly large interior, is still electrifying to watch after almost half a century. The Doctor doesn't even appear until almost halfway through, which gives him an air of authority and mystery. The great lines - "Have you ever thought what it's like to be wanderers in the fourth dimension? Have you?" - are all there.
The remaining three episodes, where the Tardis crew are captured by and escape from a Stone Age tribe who have lost the secret of fire, are OK. The second episode, with Susan's surprise that the Tardis has not changed shape, and Ian and Barbara trying to work out what to call the Doctor, is the most interesting.
The Underwater Menace, from Patrick Troughton's first season in early 1967, is notorious - even the normally upbeat Howe and Walker describe it as "undoubtedly the weakest of the second Doctor's era, if not of the sixties as a whole". Fortunately, in a way, only episode three (out of four) survives, and today's fan can buy the soundtrack with narration by Anneke Wills who played Polly (the story featuring her, Ben and new companion Jamie). This means that we are not subjected to the awful production values and can let our imaginations fill in for the cheap-looking sets. As a sound only production it comes close to succeeding, with the main problems being the baffling ballet of the fish people in episode three (which in fact becomes more rather than less confusing when you actually see it) and the utterly clichéd villain, Professor Zaroff, who actually ends the third episode by declaring that nothing in the world can stop him now. The director, Julia Smith, went on to create EastEnders; this cannot have been a high point of her early career.
It does feature the most extensively featured Irish character in any Doctor Who story, P.G. Stephens' trapped sailor Sean (who is teamed up with Jacko, a trapped Asian sailor played by Paul Anil). As I have previously noted, there is not a lot of competition. It is not fair to say that he has "the least convincing Irish accent in television history", as he has a long acting career both in Ireland and England (playing mainly Irish parts, including a comedy IRA bomber), but he is certainly as wobbly in his acting as any of the rest of the guest cast, especially in the deeply embarrassing scene where he urges the fish people to revolt.
The Faceless Ones: Set in July 1966 in London, the established companions subject to brainwashing and written out after the first two episodes, seems a bit familiar? Though in fact the story is a startling contrast with The War Machines in many ways. The most striking difference is that it is much more boring, stretched across six episodes set in Gatwick Airport, which is somehow not as exciting as the Post Office Tower. I have to say that I listened to most of them last Wednesday while on a flight from Kosovo back to Brussels via Ljubljana, not at all sure if I was going to reach my destination, so it struck a bit closer to home than I normally like my Who to do. But really, the Chameleons' predicament makes no sense, the resolution makes no sense, the departure of Ben and Polly makes little sense (though the Doctor gets a nice wistful line as they go) and the plot barely progresses from episode one to episode six. I do wish Pauline Collins had stayed on as potential companion Sam Briggs, rather than the dismal Victoria - that would have been a tension worth watching, as Jamie has already snogged her twice. But it was not to be.
Personal fact: I was born on the Wednesday between the broadcasts of episodes 3 and 4 of this story (by this point the Doctor Who cast were filming the Evil of the Daleks). Continuing the theme of the story, that same day Captain Terence O'Neill, the Prime Minister of Northern Ireland, sacked his Minister for Agriculture due to a property scandal involving an airport.
Anyway, An Unearthly Child is a must-see; the two early Troughton stories are not.