A computer system comprising a central processing unit (CPU), a memory circuit, an I/O coprocessor, and an input device comprising a touchpad and two joysticks positioned one to each side of the touchpad. The input device interfaces to the CPU via a serial data link to the I/O coprocessor. The touchpad has a default template graphic image inscribed on or in the touchpad surface and has a retainer for removably securing template overlays to be used with the touchpad instead of the default template.