You can plug a huge external monitor into the little EEE PC and get up to something like 1600x1280 rez.
But that kind of defeats the point of having a little bitty computer.
These 'minidesktops' are coming up strong on the market, Asus has one that attaches to the back of an LCD screen with a couple screws.
The problem with using a netbook in the configuration with external monitor is heat, to be honest. Better to get something that's built towards that use. And indeed, I've one on order right now exactly for this purpose, with plans on donating my wife's existing desktop as soon as I get it setup.