In my opinion as it stands... software and interfaces have been designed around the keyboard and mouse, so it's quite obvious a lot of people can't comprehend how touch interfaces would work.
For daily use, emailing, word-processing, etc -- touch screens ultimately aren't effective using our current operating systems.
There are of course many, many uses for touch and multi-touch screens. They are in kiosks, grocery stores, ATM's, subway stations, etc.
Development languages are rapidly deploying touch events and API's for everything from single touch to multi-touch devices and displays.
It's coming, it just has to be deployed in a manor that will benefit the regular user.
To be honest, I won't enjoy holding my arms out to touch my screen, thus the reason why I don't think it will be deployed in this manor.