Intel is putting so much into this as are many manufacturers - Lenovo, BenQ, Compal, et al - for the platform to fail on a usability level. Whether the public buy it remains to be seen.

Agreed. But isn't this where Mobile Linux, Mobile Ubuntu and the rest(?) comes in to play.

As we can see from the videos I linked to earlier in the thread.

x86 compatibility is probably going to make the biggest difference on the MIDs.. more existing OS can be squeezed into them (Hackintoshes, all flavor of linux and BSDs) and some ppl will see an advantage to be able to 'fallback' to their Windows OS.

FALL back. Sure.

Anyway, a backward compatibility to a known interoperability.

From personal experience, there are not many devices that would be a substitute to the Nokia Tablets, however, there are a few that are close in their own ways:
- the Sony Mylo: suitable and just about an N800 with a keyboard; not customizable though
- Windows Mobile PDAs: can do a lot, however those with a keyboard will be a smartphone and cost as much as your E90
- Eee PC: already stated here, you will have Linux and other items, but its not a pocket device by any means.