I know I'm pissing in to the void with this comment, being buried on page 7 or 8 as it will be, but to all the people saying that this is a blatant rip-off of the iPad --- go check the timeline of events in January. This device was demoed before iPad was announced. Just saying.
Obviously Windows 7 on a slate is going to be awful compared to the slick, focused and fully optimised experience of the iPad, but there will be a market for it. The PHBs don't want Apple, they want MS, but they also want iPad like devices. Nobody got fired for buying MS. Besides, these things will be OK for business use -- they'll have Word, Excel, PowerPoint, Outlook, OneNote -- those last two in particular might actually be useful. And they'll be stuffed full of ports and features that aren't on the iPad -- the things that geeks are 'crying out for' on the iPad. And you'll be able to program for them using VB.NET, so the hoards of cubical developers that aren't up to Obj-C can still churn out their line-of-business stuff.
Microsoft's problem is that their hardware partners are running away from Windows, so they might find they don't have the products to actually sell. My guess is that there was a very sweet deal to get HP back on board with the slate.