hmmm, I seem to remember a thread like this not so long ago... (except that one asked specifically about processors and the next improvements).
in that thread I said something like in the future is in low power and energy efficiency, with energy becoming more expensive and the green drive in IT currently, I can see environmentalism becoming a big part.
I read on the register yesterday that the new mexico government has invested heavily in a super computer, that they hope to make self sufficient by renting out clock cycles to buisiness.
Linux is gaining more and more market share and appearing in many homes across the world, mostly because of it's less restrictive license nature, abundance of applications and the fact that anyone can use it.
internet connections are getting faster, it's the case now that in a lot of places you can get a connection to your home, that as little as ten to fifteen years ago was the kind of speeds that were called high speed and reserved for expensive corporate networks...
other relevant tech that spring to mind is the low power wind up laptops that are for 3rd world aid.
My best guess for the distant future of computing at home will be away from the current model, and a step back in history to the dumb terminal approach, it's already that case that with applications like Citrix you needn't install software on the local computer and can run programs all over the world from inside a web browser.
I envisage that all computing may become like this, where a central computer is setup and people have low power 'dumb terminals' in their houses that connect to this massive supercomputer like machine.
practically everyone is a winner, for a much lower budget that the cost of ownership of a PC, people will be able to connect to a massive computer running more applications than they could ever feasibly own, (all assumed under a gpl style license?).
all administration is taken care of by outside people, with all data being piped to your house at speed over high speed broadband.
your computer is literally a monitor with a network connection in it (possible wireless) and you have a keyboard and mouse (if the traditional input method even survives!)...
/dreaming