If you've been curious about just how well the ModBook handles pen-input - and whether it's truly a great drawing tool or simply a stop-gap before Apple bring a tablet out of their own - then you'll be wanting to check out SlashGear's exclusive MacWorld video of some impromptu artwork being created.
As a Windows Tablet PC user, I'm quite impressed. Ink seems to flow relatively nicely and is pretty smooth, and while there's some parallax from the viewpoint of the camera I'm sure that's reduced if you're using the ModBook head-on. Still, not quite as slick as, say, a Microsoft tablet using the marvellous ArtRage, though.
Will people buy it? Oh yes, I'm sure they will - and I bet the company is already planning models with smaller screens for extra portability. Hopefully this will be the kick in the ass Apple needs to roll out a tablet of their own.