When my son asked me for a computer, I did what most geeks would do and built one myself. However, if you need a computer for a kid and either you can't build one or you want an all-in-on machine Kid Computers has one just for kids.
The machine is called the Kids CyberNet Station and is an AIO machine with a 19-inch screen. The system has an Intel Dual Core E5200 CPU and that 19-inch screen is touch sensitive. Other features include 4GB of RAM and 500GB of storage.
The AIO machine has Intel GMA3100 3D enhanced graphics and HD audio. The machine ships with software packages for kids ranging from K to 12th grade. The big catch is that the machine is very expensive at right under $2000. You can certainly get more in an AIO package for that price.