So the tv out is used mainly for:

1. Game console replacement
2. Desktop replacement
3. To show\share media (audio, video and pictures and presentations)

I think #1 is more relevant for portable game consoles where the hardware and infrastructure are already in place in the first place (game developers, control system, etc).

For #2, yes I'm sure this is in our future where we all have a personal 'black box' that acts as our computer system and docks it to screens whenever we need one and it acts as a PDA\smartphone when on the move. I the feature to 'dock up to big screen' is best implemented as an external and optional dock\dongle so as not to increase the price\size\weight for a feature that we may not use every day... not to mention, the OS and Apps may not be ready yet to do the heavy lifting of desktop computing at the moment. I think UMPCs are way ahead on this front atm.

#3 is probably the one with the most interest and what the Internet Tablets are most prepared to do at the moment. But it's already a common feature among digital cameras, many of them comes with an AV-out cable that you can hook up to TV to show your medias on. It's also probably quite small to physically implement since it's quite common even on really small digicams.

I'm ok with getting an extra cable to do #3 with minimal increase in size\weight. #2 and #1 are not really in my radar though.