I image having a set of devices that are totally synced in terms of their contents, and you choose the device you want to work on based on factors like requested screen size, input abilities, additional hardware, etc. Here is my list of devices from smallest to biggest:

1. Wrist watch. (I want to be able to sync at least the calendar to it)
2. Mobile phone with or without keyboard.
3. Tablet.
4. Netbook
5. Desktop
6. Television

E.g. if I start off writing something on the phone and realize that I need a real keyboard I should be able to just pick up the netbook and just pick up where I left off.

And btw, I wouldn't want to kill the desktop computer because it is the most robust of the lot. If the screen or the keyboard breaks you buy a new one. You want a stronger graphics card, you just get it. The integration of devices like mobile phones and laptops means that you pay premium when you have to repair or update them.