[Android Q&A, Help & Troubleshooting] SmilerOnline:
Well lets look at how we could achieve this with todays technology.

Input:

Bluetooth Mouse & keyboard.

Output:

Wireless display with support for older displays using something like Chromecast.

Graphical User Interface:

A secondary Launcher/Application (Which could potentially see companies like MS & Canonical developing their own UI's and Charging for them if required).

Home & Office use with one device:

Home would be the default UI, but when your device has used NFC to log into the office it would automatically enable your Office profile/UI for a certain length of time (requiring you to log back in after a set time or manual log out via another NFC tap).

This would be very useful as it would enable you to take your "desktop" environment anywhere with you and connect to any HDTV with Wireless display/Chromecast support.

Applications:

So if like me you are finding your phone to become ever more a better solution to your digital needs and you only require your desktop for apps which work better with larger displays (Videos & certain games) you will find this very useful.

Games:

Now games could become ever more better as they could be controlled using standardised control inputs (game controllers could use standardised input methods allowing you to select any compatible controller to best suit your needs) or even a driving game could allow you to see the game on a HDTV yet be controlled with the accelerometer for steering and the right of the devices touch display would be the accelerator and the left of the display would be the brakes for example.

More Business Solutions:

If you could wirelessly connect to the office display then show a powerpoint style presentation that would be great because the very device which stores the file would also be your controller to move to the next/pevious slides.

Media:

Music could possibly be stored in the cloud so when your on the move you can listen to your music as many of us do now, but when connected to a large display it could utilise the large display and speakers to show a music video too!.

Photos could be viewed on the large screen and the next one to be displayed could be select on the device (allowing the use to avoid showing anyone pictures which they don't want other to see - ie: pitcures of you and your friends whilst your parents/grandparents are in the room...).

The TV Guide:

The TV Guide would become a very interactive thing which allows you to see what is available on other TV channels without other people in the room being limited to viewing the content they are trying to watch in a small box in the corner of the display...

These are just some ideas of what is possible, but I know that you could do so much more with this and with 64-bit technology coming to many mobile devices soon that will make it so much easier for devices to process all of this data at once without any serious lag!.

I would love to see a group of developers on XDA team up on an open desktop (secondary) launcher to run alongside the users primary (phone) launcher. if there was a project like this with an open framework to develop apps for I'd be happy to start developing apps for that or separate UI's to run alongside my current (Phone/Android) apps UI's.

Edit:

Also remember that this could be utilised in other ways too eg:: connecting your device to your car and your device could deliver your navigation & music to your vehicles display whilst getting important traffic/weather news using your devices network connection!.