The hypocritical, Cliff Richard-loving lefty activist who was convinced that he was a Marxist rebel, a poetic genius, the voice of an entire generation and the most well-liked and attractive member of the household; he was spectacularly wrong on all counts.
Attention Whore: Oh yes. Almost everything he says is just to get people to pay attention to him.
Bad Dreams: Subverted; He's actually having a rather pervy dream after he thinks he's killed Neil, only for his conscious to wake him up and scold him, reminding him he's supposed to be "Wracked with wemorse."
Blatant Lies: He insists a dress Neil finds in his wardrobe isn't his, despite it being in his size and having his name on it.
The psychotic but strangely child-like punk who couldn't go an entire episode without destroying something — or, usually, several somethings.
Absurdly Youthful Mother: Vyvyan has one, whom we also meet in "Boring". The actress, Pauline Melville, is only nine years older than Adrian Edmondson.
All Men Are Perverts: Spends the entire time when Helen Mucus is in the house staring at her chest (very obviously and even moving his chair closer), happily volunteers to wear tights a girl might have worn, briefly checks out Amazulu when they perform in the house during "Time", tricks the washing machine into opening its hatch by claiming to have Felicity Kendall's underwear, etc.
Ax-Crazy: One of the most violent characters in a Britcom ever - played entirely for laughs. Vyvyan is perhaps the closest live action TV has ever come to a Warner Bros. animated character.
Berserk Button: It's fairly easy to annoy Vyvyan, but he really hates The Good Life and being reminded he has a girl's name.
Blondes are Evil: Possibly. He's not exactly evil, but he is the most violent member of the house, and although Vyvyan never stated if his hair was dyed or not, his actor had extremely blond hair naturally.
Charles Atlas Superpower: Vyv can survive decapitation, eat pretty much anything and perform absurd feats of strength (such as pushing the wall of the house just so the lads can hook up the video).
Disappeared Dad: When he hopefully asks his mother, "How's Dad?" she responds, "Honestly, Vyvyan, I wish you wouldn't ask me that! ...You know I have absolutely no idea who he is!"
Drives Like Crazy: Any time he gets behind the wheel of his Ford Anglia, he crashes it into something. This should probably double as Foreshadowing, as he is driving the bus when it crashes over a cliff.
Genius Ditz: Despite being unable to tell time and generally being Axe Crazy, Vyv has a surprising knowledge of how to rig up machinery (as evidenced by his souped-up vacuum cleaner) and can be surprisingly insightful and even manipulative. Plus, he's a medical student.
Hidden Depths: Some episodes imply Vyvyan isn't quite as stupid as he pretends to be; He starts accurately describing how the human body produces vomit in "Time", tricks the vampire into revealing it's a vampire in "Nasty" and his potion to turn Balowski into an axe-wielding maniac did actually work. When he actually does go to uni, he's a medical student.
Super Strength: Can kick a sink over, push the entire house forwards, bite through brick, lift Neil over his head, survive being decapitated...
Tsundere: Surprisingly, but Vyvyan has the most friends out of the group, as seen in "Interesting", but Vyvyan claims he "doesn't like any of them." He's also like this towards SPG; SPG is as much on the receiving end of Vyvyan's violence as Rick or Neil, (although SPG usually provokes him) but Vyvyan still cries when SPG dies.
Neil (Nigel Planer):
The whining, put-upon and suicidal hippie who acted as the dogsbody for the entire house and is convinced (accurately) that no one likes him and everyone is out to get him.
Adorkable: He has his moments, particularly when he gets excited about going on University Challenge.
Berserk Button: He very nearly hits Rick with a frying pan for mocking his flares.
Friend to All Living Things: In "Flood", he manages to rescue some kittens on the way back from the shops, and mentions in one episode wishing he could live a pastoral existence.
Gentle Giant: The tallest of the guys, but he's passive and generally rather calm.
Genius Ditz: Though he often is Comically Missing the Point, Neil is shown to be fairly clever, is the only one who bothers to study properly for university challenge, quite knowledgeable on Oscar Wilde and he scores the best out of the lads in their exams.
Hey, You!: Rick and Vyvyan both refer to him as simply "Hippy" a few times.
Hopeless With Tech: He can barely use a phone properly and when he tries to use a washing machine, it spits out his clothes out of disgust. He's convinced machinery hates him.
Iron Butt Monkey: "Time" has him clocked on the head several times with little damage. When Vyv throws a Molotov Cocktail at him and Rick in "Sick", despite destroying the wall between his and Rick's room, the only effect it has on him is temporarily clearing his sinuses.
The Charmer of the flat; a smooth, flash and mysterious con-artist who tried it on with every girl he came across, still waiting for it to actually work.
Affably Evil: Sort of. He's not really evil, but he is implied to be involved with numerous criminal dealings and occasionally acts immaturely or insane, such as in "Oil". Despite that, he's also probably the most likable member of the flat and seems to be an honestly nice person at times.
Blackmail Is Such an Ugly Word: He is revealed to be blackmailing his tutor in "Summer Holiday", which explains how he managed to get through the year despite never going to university.
Muses he might ask for a PHD from the Dean, implying he has dirt on him, too.
In the opening credits for the first series, he's seen bribing a lecturer at his graduation.
Casanova Wannabe: Although the reactions of the girls at the party imply that he's less of a wannabe than Rick, a later episode confirms that all four of the lads are virgins.