Majority of the touch tablet using Android (or Apple iOS, Windows 7) system. RIM BlackBerry just release a tablet name PlayBook which use QNX.
Most people have not heard of QNX, but QNX has been in the market for more than 10 years time, it focus on embedded system, especially in automobile industry.
I was once very impressed by QNX on PC. QNX has a demo disk image, the system was compress on a 1.44Mb disk. The system can boot from the disk, which includes kernel, operating system, GUI and a browser.
RIM (Research In Motion, the company makes BlackBerry) acquires QNX in April 2010, in less than 6 months time, RIM release a tablet powered by QNX in this September.
Is good to have RIM join in the market with a different operating system. You can watch the BlackBerry Playbook promotion video on youtube.