Bob 'n' Dave. Written by the boys from Bristol, The Three Doctors remains somewhat of a guilty pleasure of mine. It's padded, is perhaps Sergeant Benton's greatest moment and features many of the era's most redoubtable guest stars in Roy Purcell, Clyde Pollitt, Rex Robinson and Stephen Thorne. It's also interesting to note that it's in this serial that the Doctor finally breaks the Brigadier's mind when the series' other character known by title only decides that Pertwee has somehow regressed to Troughton.
This is, in a way, a bit unfair. The Brigadier's seen enough crazy stuff to make him believe anything is possible so why shouldn't Pertwee change back into Troughton - it's hardly like the Doctor to explain, in-depth, the Time Lord penal code. It's the pigheaded refusal to listen to Benton which makes the Brigadier seem so chump-ish here. Well, this, and it's made worse by prior scenes (eg. from The Mutants where they emerge from the TARDIS and say "Don't tell the Brigadier, he'll never believe you"). By this stage of the series' evolution, The Brig (capital T, capital B) had become a parent figure that children - the most anti-establishment figures of them all - poke fun at for having no imagination. That Pertwee's Doctor was the archetypal Mother Hen, swooping in to protect her children makes this all the more arch, seventies bliss.
No matter how excellent in retrospect, it wasn't Season 7 I first fell in love with. As a toddler, I became infatuated with the UNIT family (Brig, Jo, Benton, Yates, several Jimmys and Corporal Bell), the Master, Daleks - and most definitely, the Pertwee Doctor. He was my absolute, unassailable favourite until I really got to grips with Troughton in my early-to-mid twenties.
That said, Baker/Martin's scripts were rife with pun-sational or schmaltzy dialogue and they evidenced an ever-increasing desire to create marketable catchphrases ("Contact has been made") so that The Kids could tell what the bad guys were up to. They, more than any other writers, were responsible for most of the "Don't tell the grown-ups" moments; unsurprising considering their background in childrens' television.
Stephen Thorne. I love Stephen Thorne as Omega in this, I always have. While you can slag off Bob 'n' Dave all you like for occasional cringeworthy lines ("I got the feeling they were more deadly enemies"), the idea of a man kept alive by will alone - coupled with the imagery of Omega removing his helmet to display nothing beneath - is absolutely brilliant television. Thorne does absolute justice to the character, moving between inarticulate rage and boasting arrogance with finesse Bruce Purchase could only splutter at. Thorne's rich, deep vocal portrayal makes Omega what he is despite a physically imposing frame. Favourite line: "If I exist only by my will, then my will is to destroy!" - delivered with such unhinged insanity that you actually end up feeling for him.
Troughton. While there were elements of Troughton's Doctor which emerged throughout the serial, he was actually written quite differently from his time as the lead. He's impish, but without the occasional gravitas which typified many of his best lines. It's nice to see him - and painful to see Hartnell, who was only 65 but looks every day of his character's 400 years - but you feel his Doctor is very much thought of as "the funny one".
In two words: Childhood relived.
* 51-word sentence. Personal best!