Cable with QAM modulation can already do real time streaming of HD to HD-DVRs. I have had one for a while and it works quite well. I just wish my cable company would offer some decent movies on the HD On-Demand channel.

These services of the future may use something slightly different then the present internet. Bandwidth in general is still expanding and getting faster and cheaper, so in a few years things may be radically different then today, until then we have HD-DVD and Blu-Ray to fight over.