It takes a lot to faze the hardened computer nuts of Times Online, but you could hear a pin drop here when Apple's new 27-inch iMac arrived this morning.

Our machine was the £1,349, 3.06GHz dual core model, but for £250 more, a faster quad core version is available.

As with all new Macs, setup is a cinch. You take the machine out of the box, plug it in and hit the power button. Then answer a few questions about internet, email and so on, and you're set up and ready to go.

Now, I spent much of yesterday working with Windows 7, which I think is the best OS to come out of Redmond for years. What struck me, however, was just how little you get with it. With a Mac, everything from e-mail programs to music-making is included as part of the package. The only omission is a decent word processor. Text Edit is OK for basic typing, but if you want more, a quick download of the free OpenOffice is only a couple of clicks away.

In truth, though, none of this is what grabs you when you first get the iMac up and running. It's the screen. All 27 LED-backlit inches of it, 2560 by 1440 pixels in the same 16:9 ratio as a widescreen TV set, rather than the 16:10 of previous iMacs.

We went straight online and checked out the natural history series Life, in HD on the BBC iPlayer. Every detail of the programme I'd watched the week before was rendered perfectly.

Of course, a screen this size begs the question: can it be used to replace a TV set, leaving you with a screen that does everything?

Frustratingly, the answer is yes, and no. The 27-inch iMacs are the first to allow signal input as well as output from the onboard Mini DisplayPort. This is a welcome addition, but surely it's not beyond Apple's capabilities to include HDMI, which is precisely the sort of fuss-free interface that Apple has long championed?

If this machine came with a couple of HDMI inputs, it would fly off the shelves. At a time when HDMI is becoming common even on £200 notebooks, it's disappointing that Apple should miss such an obvious trick.

As it is, Apple has confirmed that the iMac will work as an external monitor only, and that third-party solutions to connect domestic devices to the Mini DisplayPort are on their way.

For true innovation on the new iMac, we must look elsewhere. For the first time it comes supplied with a Bluetooth wireless keyboard (not full size, with numeral pad and forward delete the most apparent losses) and a Bluetooth Magic Mouse.

It is the mouse that has been attracting the attention. It is beautiful to look at and feels instantly comfortable in the hand. Apple claims nothing less than the reinvention of the computer mouse. But then, Apple would. What it is, in fact, is an extension of the trackpad technology used in Apple's laptops to the surface of a mouse.

Thus, it's possible to control the computer without much clicking or movement. One downward slide on the mouse's surface moves a screen down, and a two-fingered sideswipe can move you between photos or act as a back button in a web browser.

The mouse looks wonderful, and though the single-finger actions work smoothly, the results were less successful with the sideways swiping. My sweaty old fingers tend to stick to the surface, while other users complained of having to arc their hand uncomfortably to achieve the desired effect.

As the afternoon wore on - and I am typing this on the iMac now - the mouse grew on me a little more, to the point where returning to use a track wheel felt peculiar after the smooth surface of the Magic Mouse.

So, is the new 27-inch iMac worth your money? For a computer with no Blu-ray drive and no HDMI ports, £1,349 is a big chunk of change. But then, if you add a USB-based HD TV solution, or a cheap external Blu-ray drive, this may be all the kit you ever need, your music jukebox, TV set and PC rolled into one. Apple's addition of an SD card slot below the DVD drive makes external content such as video and photos, even easier to load.

The new iMac is on sale now. Magic Mouse is available separately for £55.

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