There's an ongoing trend for all things modular. Many companies showed off prototype designs for sectioned-out PCs during this year's CeBIT show, but if you want an early start on the trend, then external storage is ahead of the game.

LaCie's Brick drive (shaped like a large Lego block) showed off the concept of interlocking, stackable drives a year ago, and now hard drive pioneer Western Digital is getting in on the act with its My Book concept. Not that it's the meatiest of principles: get a box that stacks nicely, stick a hard drive inside, add a USB interface, and go.

The styling is confusing. You'd imagine a case as large as this would contain a pair of drives, perhaps working in a RAID array. Not so.

A 320GB drive nestles inside the large case, confirming that the looks of this device were a stylistic decision - and why not? In the company of designer external drives from the likes of Lacie and Plextor, you need to do something special to stand out.

In this case the original X-Box was a clear point of reference: everything from the black plastic grooves to the glowing green power button give off the same aura.

Microsoft can't claim to have hidden morse code messages between its air intake holes though, so Western Digital has one up on them there, and the obvious literary inspiration means the My Book stacks neatly in a horizontal fashion.

This isn't just some fashion item, however. Performance is everything, and spinning at 7,200 RPM, the My Book is faster than most of its ilk. Unfortunately, all that speed drinks the power, and the modular nature is questionable in light of the required AC adaptor.

At least there's intelligent power management: the My Book automatically switches on with your machine. You're provided with Google's suite of media management tools even though My Book needs no setting up to get running.

Naturally the My Book is a bit pricier than a similar drive would be without the casing, but we think that it's definitely a price worth paying. Alex Cox