People who buy computers agonise long and hard over memory, monitors and processors. But when it comes to the keyboard, most of us simply accept what we are given. That may be changing. In September, Microsoft, the software giant, launched its Natural Keyboard as an alternative to the straight-from-the-box offerings of most PC builders. According to the company, sales are running well ahead of expectations.

The new keyboard looks and feels quite different from a standard 101- key flat keyboard. The qwerty keys are divided into two distinct groups, one resting under each hand. The whole unit is quite large and feels solid. It is raised in the middle, sloping away towards the edges, and the space bar and command keys are far larger than on a conventional keyboard.

This layout leads the user to adopt a more natural, and therefore comfortable, posture. It encourages the typist to use all 10 fingers, rather than pecking at the keys with one or two, and it is perhaps most suited to users who can already touch-type.

The keyboard's front can be raised or lowered to allow for differing desk heights, and it incorporates a sloping wrist-rest, to support the hands when not typing. The package includes an on-screen ergonomics guide - and extra function keys for use with the Windows interface.

As well as selling the keyboard as a stand-alone product, Microsoft expects PC manufacturers to offer it as an option, in the same way as buyers can specify a Microsoft mouse with many computers.

But Microsoft is not the first company to bring out an alternative keyboard. Apple offers standard, extended or adjustable units for its systems, and PCD Maltron produces a range of more specialist keyboards for both the Macintosh and PCs.

One Apple keyboard splits the left-hand and right-hand key sets with a hinge in the middle; the function keys and numerical keypad form a separate unit. Like the Natural Keyboard, it has wrist-rests, but these can be removed. The keyboard can also be clicked back into the conventional, straight key position - which may be an advantage on shared machines.

The Maltron keyboard takes the split keys concept farther, placing the two groups in deep wells with the number keys in between. Not only are the key groups raised in the middle, as on the Microsoft keyboard, but the depth of each key within the wells varies according to the length of the finger that operates it. At £375, it is perhaps most suited to heavy keyboard users, but it comes with a solid reputation for helping repetitive strain injury (RSI) sufferers to return to work.

Microsoft and Apple are both understandably cautious about being drawn into the legal debate on the link between keyboard work and upper limb disorders. However, both firms provide detailed advice on ergonomics with their products, from the need to take frequent breaks to posture and desk layout. Microsoft also includes warning stickers on the keyboards - particularly useful in offices, where individual users will probably never see the manuals.

An improved keyboard alone is not going to guarantee trouble-free computing, however. In the longer term, technologies such as handwriting or voice recognition may well render the keyboard obsolete. But if the choice of keyboard becomes as considered as that of any other part of a computer system, users can only benefit.