I'd absolutely love to see some benchmarks compared to an Intel Atom based netbook with integrated graphics...
I'm not so sure about the whole laptop dock thing, but it might be useful. As long as they can get a standardized input going for all of their phones then anyone could use the dock as a portable keyboard and mouse for their phone. It should only be $200 - $300 for the shell of a laptop, but everytime you get a new phone it would be like getting a brand new machine.
The HD multimedia dock is really nice, but can we do the same thing without having to have the dock? That's the one thing that kind of sours the deal about the Zune. Use a bluetooth keyboard and mouse, and only have to carry around one hdmi cable to plug into a display. It would be just like having a computer except you can fit everything you need in your pocket.
As a side note, this definitely makes microsoft's announcement the other day much more enticing. No wonder they want to make sure they support ARM if the next generation of phones can work just like a pc.