My favourite film: Ghostbusters

Citizen Kane? Some Like It Hot? I can see their merits. But it's busting that makes me feel good.

Admittedly, a significant portion of my Ghostbusters adoration comes from two strands of nostalgia, one that is entirely solipsistic and one for the friendship that shadows the whole of this awesome little comedy. But nostalgia aside, this has always seemed to me the finest mainstream 1980s comedy (the highest of accolades in my book), beating my second and third favourite films, Ferris Bueller's Day Off and Trading Places, by virtue of its sweetness. This movie is the opposite of cool – and that, too, is a very high compliment.

I did not like scary films in 1984 and I do not like scary films now (my definition of "scary" remains unchanged) and yet, incredibly, my mother took me to see Ghostbusters when it came out. Even though, just a month before, she'd had to carry me out of the cinema screaming like a five-year-old banshee during a screening of the 1971 film Willy Wonka and the Chocolate Factory, when Augustus Gloop got stuck in the pipe. Nonetheless, despite Ghostbusters' – still terrifying, thank you very much – opening scene in the New York Public Library, I knew from the first time I saw this movie that when I grew up I wanted to be Bill Murray, marry Dan Aykroyd or, ideally, both. Those ambitions remain unchanged.

Aykroyd, with typical generosity, has said that at least 50% of Ghostbusters' success was due to Murray. As Dr Peter Venkman, Murray perfected his irresistible sardonic hangdog persona, one he'd already made famous in Meatballs, Stripes and – my all-time favourite Murray performance – Tootsie. Yet all of the major actors play their personae to perfection in this movie: Aykroyd as the sweet friend, Rick Moranis as the hapless nerd, Harold Ramis as the egghead, Annie Potz as the nerdy-but-sexy sidekick and, most of all, Sigourney Weaver as, alternately, the glamorous love interest and sci-fi demon (to some people, Weaver will always be Ripley; to others Dian Fossey; to me, she will forever be Zuul, panting like a dog and trying to nip Murray's finger).

These actors give the film its core of sweetness because you can see the very real friendship between them, particularly between Ramis and Aykroyd, who wrote the film together, and Aykroyd and Murray. Often Aykroyd is visibly choking back a smile as Murray riffs. (I have often thought that my favourite Murray line in the film – "We've been going about this all wrong! This Mr Stay Puft, he's a sailor, he's in New York; if we just get him laid we won't have any problem!" – has the distinct smack of an ad lib.)

It may seem unimaginable now that, considering it contains such classic comedy lines as "Back off man, I'm a scientist" and, most famously, "Yes it's true. This man has no dick", Ghostbusters was not originally envisioned as a comedy. Aykroyd wrote it as a serious film, a plan that sounds a little less ridiculous if one takes into account the fact that Aykroyd has had a lifelong interest in spiritualism (he also – fact fans – has webbed feet and is married to the "dream woman" from Wayne's World. Dan Aykroyd is pretty baller). Director Ivan Reitman thankfully convinced him to turn it into a comedy and Aykroyd then proceeded to write it for himself and his best friend, John Belushi, to help the latter's film career emerge from its post-Blues Brothers doldrums. Tragically, Belushi died before the script was finished and so the star-making part of Venkman went to Murray, who had known Belushi. One of the last photos in Judy Belushi's biography of her husband shows a grief-stricken Murray placing a flower on Belushi's coffin.

But Aykroyd still managed to get his friend into the picture. Slimer is a total homage to Belushi, sharing his tendency to eat food off other people's room-service trays left in hotel hallways. More obliquely, the movie was made by Black Rhino Productions, which is Aykroyd's production company – named in honour of a dream he had after Belushi died, in which his friend's face was on a charging rhino. There are many reasons why Aykroyd feels – as he has often said – a particular fondness for this film.

Despite his interest in spiritualism, Aykroyd wisely underplays the spookier elements, focusing instead on the geeky science: the proton packs, the containment units, the streams that must never be crossed. All the best 80s comedies have an element of Crap Science to them, from Short Circuit to the greatest 80s film science experiment of them all, the DeLorean with the flux capacitor. This is my kind of sci-fi: gleefully nonsensical, sweetly nerdy.

One of my favourite things about this movie is its graphic cartoonishness: the Ghostbuster uniforms, the ghostmobile (AKA Ecto-1, of course), and the Ghostbusters insignia are as recognisable today as they were almost 30 years ago. Every Halloween since, packs of increasingly aged men have gone out dressed as the Ghostbusters in New York, and every Halloween since that I have squealed with joy at the sight of them. But what I really love about it is its setting.

Many of the jokes in Ghostbusters stem from the idea that, ghosts aside, Manhattan itself was an out-of-control wild west place, a Gotham city where a man could collapse against the windows of the Tavern on the Green, the ritzy restaurant that used to be in Central Park, and the diners would simply ignore him. Trash is piled on the sidewalks and Checker cabs whizz round corners: this recreation of New York, 1984 – the New York of my childhood – is still how I think of the city, even though I live there now and Manhattan has, for better or worse, changed a lot since. Ghostbusters is as much a love letter to New York as anything Woody Allen ever wrote, and a much less self-conscious one at that. Even the hilarious anachronisms give me a sentimental frisson: Lewis being mocked for his love of vitamins and mineral water, Aykroyd and Murray chuffing down fags while toting nuclear reactors on their backs, the bad guy being – and this I particularly enjoy – the man from the Environmental Protection Agency. These all look particularly anachronistic in New York 2011, and I can't help but feel the city is a little poorer for it.

Shaun of the Dead owes an enormous debt to Ghostbusters (and that film's director, Edgar Wright, has spoken often of his admiration for Reitman) in the way it showed normal people reacting with relative normality to an invasion of the undead. In Ghostbusters, those details are hilariously New York-ian, such as the groups of priests and Hasidic Jews you can just spot praying outside the ghost-inhabited apartment buildings and Larry King chatting dryly about the spooky invasion on the radio. But my absolute favourite moment in the film is at the end, when a doorman brings Ecto-1 round after the Ghostbusters have saved the world – or at least Central Park West – from destruction. Despite having battled a giant marshmallow man, Aykroyd still has a couple of dollar bills in the pocket of his ghost uniform to tip the doorman. You cannot get more New York than that.

The one big fault in the film is, notoriously, the character of Winston Zeddmore – written for Eddie Murphy (he turned it down to make Beverly Hills Cop) – who feels pitifully pointless. Yet news that Murray has refused to make a third Ghostbusters film until Ramis and Aykroyd sort out poor Winston's role sort of makes me love them all even more.

The reason I was able to deal with that terrifying opening scene when I was five was because the men on screen looked kind, because the city they were in looked so familiar and because they said things that made me laugh until I wet myself a little. Ghosts may come and go, self-destructive performers die all too prematurely and New York may gentrify – but those things have never, ever changed.