It's interesting that data buses seem to be a dying technology. S-ATA is clobbering the old hard drive bus (and isn't someone wokring on a point-to-point SCSI system also?), PCI Express is taking care of the old PCI bus, and USB is . . . just sort of filling a hole. Ethernet slaughtered its competitors long ago. Everyone's going point-to-point now. Theory as to why - chips are getting cheap enough to make central hubs extremely easy to implement with only simple logic on whatever's connected to the hub. Sort of a client-server setup - they're so successful everywhere else, why not in hardware?
I can't think of anything in the Computer of the Future (about two years from now) that will be a shared bus, actually . . .
Other interesting things - everything's going serial, not parallel. Chips are so cheap that you can handle an ultrahighspeed serial connection, but parallel connections are wider and have interference problems.