Comment Games and Stories before Computers (Score 1) 556
A desktop unit would be safer and more practical for a two year old. The CPU and screen can be placed out of reach and sticky fingers and tantrum fists will only ruin cheap keyboards and mice.
If you must get a portable the OLPC would be the best for a child and the G1G1 program will provide another child with a learning tool.
At two years of age a child should be learning all sorts of things. However, ingraining and encouraging the child to become a socially isolated, sedentary keyboard potato is not recommended.
Wooden blocks, simple musical instruments, crayons and paper, large packing boxes, pillows to build a fort, dolls, picture books - these will encourage learning and imagination. Computers, not so much at that age.
Children need a environment that is rich in physical and mental stimulus, is stable, and is reassuring. A computer couldn't hurt (if proper precautions are taken) but is the least necessary learning tool at two years of age.