Netbooks have revolutionised mobile computing and I promote their use as desktop replacements. Just use with perispherals to enjoy a desktop experience and then take the unit away with you.
I think that ultimately personal mobile computing will prevail and I wonder just how long the huge dinosaur like desktop chassis will continue for - just consider the manufacturing, storage and delivery issues of these things. Most of the space inside a desktop chassis is air anyway.
However, there are situations where desktops are necessary and these are mostly about security - its just harder to steal a big old desktop chassis.
However, the core processing components are shrinking fast and most of a desktop environment is taken with items that really do need to be large - the screen and keyboard and perhaps a printer (if you must).
The laptop has been revolutionisised by the entry of the netbook - it's time the dekstop also had a revolution - enter the Nettop.
The new generation of ultra small form factor desktops (Nettops) are about the size of what used to be the CD drive. In the box where once one PC was delivered you can now get devilvered 10 or more Nettops. The implications for IT support departments and suppliers are revolutionary.
What I see happening here is that the processing unit becomes the smallest, cheapest and most replaceable part. You could keep the desktop chassis and simply upgrade or repair by swapping in the processor unit - even simpler than the way we would have changed a CD drive some years ago. The processor unit could "disappear" - just becomming embedded and given away with the peripherals - certainly the screen. For now however, we anticipate mounting these units at the rear of our 19in screens.
Lets not forget that these machines are also very good for the environment - low power, small and low noise.
Could this be why Intel are moving into embedded software bedause the computer market is literally disappearing...
Here are some references for Nettops
The Acer AspireRevo Nettop with NVIDIA ION GPU 4Gb RAM, 250Gb HDD and 1.6Ghz ATOM CPU
The Pars I-Cute - These are the units I'm holding up in the photo above