I find Orkut pretty usefull and It used to be more privacy-tunable than Facebook.

I have a Nokia 770.
If N800 resolved some of the few bugs i found on it ... it must be awesome.
I love my... thing.
As someone said before, it's the nearest thing to "everywhere Internet" i've ever seen.
For something bigger you have light laptops. For smaller a decent smartphone.
Any combination would cost far less than 2K bucks and will be more efficient.