Everyone in the home will want to be watching different UberHD movies on wall-size UberHD screens. Think CinemaScope in the home, with the screens on 3 walls (or more). (Digital IMAX is 10000x7000 according to http://en.wikipedia..../Image_resolution )
40 Gbps (in principle) gets you a HD DVD in 2 seconds - http://www.voodish.c...ection-at-40gbps/ Of course, the rest of the system can't keep up, so it's academic at this point...
I think someone will find a way to saturate whatever bandwidth is available, even for one person. Of course, no one will be able to afford it, but that's not the point. ;-)
Cheers,
Scott.