By Rory Cellan-Jones
Technology correspondent, BBC News
After a few delays Apple TV has finally gone on sale, with predictions that it could be a more important product for the company than the much-hyped iPhone which arrives in June.
Apple TV offers a bridge between a computer and a television
But will the set-top box soar like the iPod, or sink like the Cube - a stylish ultra-compact Apple computer that was supposed to change the rules of the game, but was swiftly discontinued?
Apple TV is small rectangular white box with a 40GB hard-drive, designed to take content from your PC or Mac and display it on your widescreen television.
It is far from the first device to offer a bridge between the computer and the television. But the iPod was not the first MP3 player - and Apple and its supporters are quick to point out that it still went on to dominate and define the market.
Having built a hugely powerful position in the global music industry by integrating the iPod with its online store iTunes, Apple is now tilting at an even bigger prize - the online video market.
Joost was founded by the men behind Skype
With everything from YouTube to the internet television service Joost offering viewers new ways to access video, this could be the year that the online video revolution really takes off.
The old media giants will be watching nervously to see whether the likes of Apple try to steal their lunch - the billion dollar lawsuit launched by Viacom against YouTube is the first shot in that war.
But for European customers in particular, there is one big question about Apple TV - is there anything worth watching?
Because as with the iPod, Apple has been careful to tie this new product into iTunes, creating a walled garden beyond which it will be difficult to stray.
In the United States, where Apple has been selling films and television shows to download from iTunes for the last 18 months, some users will at least have a fair amount of content to stream from their computers via their wireless networks (and ideally you'll need one with the latest 802.11n standard) to their HD ready televisions.
Content is king
But in Europe, Apple has so far failed to strike the deals with movie studios and television companies which would allow it to sell video content to download.
There are now rumours that Apple is about to announce a deal to sell movies in the UK - but mainstream television content seems to be some way off.
With broadcasters such as the UK's Channel Four now beginning to sell downloads from their own sites they may be more reluctant than the music industry was to hand over distribution to Apple.
The Apple TV does offer what looks like a simple and elegant way to transfer your digital content - including home movies, photographs and your music collection - from the computer in the back bedroom to the television in the sitting room.
Those with real expertise may learn to rip video content from sites like YouTube into iTunes and then send it to their Apple TV.
But the whole appeal of the iPod has been that it offers a beautifully designed pathway into digital music for novices.
Without compelling content, Apple TV will struggle to pull off the same trick.