What's missing in that picture? Keyboard! Where would the keyboard go? Two options I can think of:
1. On the screen. Blech. I can tolerate that on the iPad / iPhone but that's because I don't type much on those devices. On a desktop though, typing is my primary input.
2. The keyboard could possibly go in front of it, but you need to move the screen away 6-8 inches. Because your viewing angle has changed, you would have to elevate the screen more vertical so you could see it. Because of that elevation and the distance from the user, you'll get gorilla arms using the touch screen exclusively.
Another issue, is the touch area of a finger is significantly larger than a mouse pointer, so all your icons would need to be a lot bigger like MS tiles, or more spread out like launchpad.
Also, how would clicking and dragging work? How would right click work? iOS has removed the need for both, but they're still needed on the desktop. I think it's a gee-wizz thing that will wear off fast and people will be reaching for the trackpad.
Don't get me wrong, that is a great surface / touch screen for artists, but for everyone else, I don't think an exclusive touch screen is practical on a desktop.
example scrolling itunes, play music, zoom in and out, simple click on link etc list can go long.
