All I can say is WOW.
Well not really, as I've been testing it in a VM so had some fun with it and I would like to reiterate my last sentiment...
Hows about that boot time? Pretty impressive even if they are 'cheating' a bit.
This is the most radical shift in Windows since '95, it may be too soon to call but I'm going to say it will be a hit. I've shown my wife and mother some bits and pieces and they really like what they've seen, my mother has just bought herself an Android tablet (the XOOM, if you must know) and I have been left disappointed by it.
Honeycomb has not hit the sweet spot for me and I do regret telling her to go for it, but it was her call and she really wanted another device as her 3+ year old laptop motherboard packed up and her phone went in for repairs ( HTC Desire S, if you must know) so she had NO internet connected devices, other than her internet TV (Panasonic Viera, if you must know) which doesn't provide Facebook access. So you can see she was kinda desperate for a device. Though I did warn her that tablets are not replacements for laptops yet.
That's where Windows 8 comes in, I believe it will be the all encompassing OS. It'll be great for corporates, buy your staff an i5 tablet with more than enough grunt to do most daily tasks and enough battery power to last the day while out at meetings. When they come in, they can dock it with a blue tooth keyboard/mouse, charge it up and continue working with either Metro apps or using normal 'legacy' Windows apps.
I think the only issue may be developer adoption, but I think Microsoft are aware of this - hence the give away of Windows 8 developer preview without registration and a whopping 5000 Windows 8 tablets at the BUILD conference to get things kick started.
My hat goes off to the softies, it takes balls to make a jump this big. Apple seem to be standing still now, even with Lion and all of it's extra features, they'll be 2-3, maybe even more years away from this sort of integration between laptop/desktop/tablet, if they do anything like this in the future. Android, well sorry matey you just haven't pulled it off (yet).