This Netvista is the best all-in-one PC around. With a Pentium 4 processor, a 17in TFT display and desktop components, it provides the power of a normal PC at a fraction of the size. You won't be able to play games on it, but there's a limited upgrade potential and if something goes wrong you'll be able to get inside to fix it.
Vnunet
Colour-coded ports at the rear of the system should make it easy to set up.