This conflates "just one device" with "make everything simpler", and sacrifices the first for the second, while it's the first I care about more. I don't mind having a Linux box with a filesystem and a command line -- I actually like that -- I just want to have all of my data available all the time, and all of my connectivity available all the time, and I'd prefer not to have to sync a bunch of devices and figure out which ones to take or leave when I'm out.
Right now I'd be happy with a device that had a dongle that you could connect DVI to, and accepted a bluetooth keyboard and mouse. Higher speed internet than my 3G is a nice-to-have, but not essential.