WATCH: The 9 best Christmas ads of all time

The nostalgic ones; the iconic ones; the ones that make you laugh, cry, buy and sigh...

It's December, and that means businesses really want to sell you lots of stuff.

Yes, the weeks (and months) leading up to December 25th are now reliably loaded with special seasonal adverts for almost every product and service around. Drawing on the public's inherent fondness for the festive season, Christmas ads come in all shapes and sizes - from nostalgic throwbacks to unashamed tearjerkers and even the occasional 30 seconds of satire. A lucky few even graduate to become truly iconic - as intimately associated with the holiday season as brussel sprouts, AAA batteries, or the Father Ted Christmas Special.

For many, there's one main indicator that 'holidays are coming'. It's not the cold weather, it's not the the town Christmas lights getting switched on, and it's certainly not the supermarket shelves filling with festive favourites (although you'd be putting up the tree in mid-August if that was the case). Instead, it's the arrival of the most famous Christmas ad of them all.

The urban legend falsely claims that Coca Cola invented the modern version of Santa Claus, but no doubt the soft drink giant has firmly associated itself with the season.

Speaking of Santa, the Coca Cola company doesn't have exclusive rights on the old Saint Nick. Kellogg's are one of the other companies to have crafted a beloved ad featuring Mr Claus. Traditional and effective.

We can't let Mr Claus have all the fun though. In one of this year's most talked about ad, Marks & Spencers drafted in Oscar-winning director Tom Hooper to help put Mrs Claus in the spotlight with their surely expensive but ultimately charming seasonal ad.

Christmas ads are inherently cynical - drawing on a beloved annual tradition to persuade us to buy more stuff. But when cult director Wes Anderson is behind the camera, you're almost inclined to forget that - well, until the H&M logo pops up to remind us of the fact. Still, this year's offering from the clothing giant and acclaimed filmmaker brings a little bit more art to the festive corporate assault.

For the last half decade or so, the 'John Lewis Christmas ad' has annually garnered the most attention and indeed affection from viewers. The promos for the British department store chain have been noted for their emotional earnestness, high production values and often quirky concepts.

Each viewer will likely have their favourite, but 2014's offering is worth highlighting - if only because penguins are inescapably adorable.

Even John Lewis, however, can't compete with German supermarket Edeka. Its 2015 offering - complete with twist ending - is the sort of viral hit marketing teams surely dream about. 52 million viewers can't be wrong...

Christmas ads often want to make you cry. Some are more successful than others at the task. One that did seem to do the job for many, however, was this Apple ad from 2013.

Expensive electronics may not be the first thing you think of when it comes to emotional family time. However, the technology giant nonetheless managed to win plenty over - and a few awards to boot - with its unashamedly tear-jerking effort about the more social side of technology.

Drawing on an iconic festive favourite for advertising purposes is a risky proposition, but this classic An Post ad manages to nail the landing. Simple yet surprisingly classy, the post office folk borrowed the style and Walking in the Air theme from The Snowman animation to create one of the most enduring of Irish Christmas ads.

Or, if you'd prefer a more darkly satirical variation on Walking in the Air, Irn-Bru has you covered with a frustrated snowman's flight over Scotland...