OneNote is one of those rare apps you'll wonder how you ever managed without it. It's basically a note-taking application where you work on sheets of electronic paper, putting down your ideas and rearranging them.

OneNote handles handwriting when used on a Tablet PC, but it's equally at home on a standard notebook or desktop for jotting down random thoughts. Speech recording is built in, and the program timestamps every scribble and typed note so that it's synchronised with the voice recording. Storage for basic voice runs to 8MB an hour, which is really insignificant.

OneNote is deliberately simple in implementation and execution. There's no macro engine, no object model and no sign of XML, at least not in this first release. However, the Office team, specifically the Word group, is taking this opportunity to think in unconventional terms about how we store data and interact with it over time.

If you have a Tablet PC, OneNote is a mandatory purchase. For desktop and laptop users, it depends on how you do your note taking and information jotting. As an initial release, it delivers a sweet spot for the pen-using community, but subsequent versions need to build on this promise and deliver a wider application that's appropriate to every desktop user.