Good evening...

My opinion is that touch on desktops will take off, ESPECIALLY with the touch All-In-One PC form factor as most of the new Windows 8 AIO PCs are touch enabled. I'm not big fan of those as you can't really adjust them other than 178 degrees.

I would look into something like Acer's touch monitors, or ones that actually slide down from a range of maybe 0-178 degree angle, along with free and available space on top of your desk. THIS, is the best way I believe to enjoy touch with the desktop. You're close to the screen and can easily manipulate things on screen. It seems that most touch monitors also have built in web cams and mics, which is a nice plus. You can even use the mic for speech commands for Windows!

It really depends on what you want to do. I believe touch is the future, many PC makers think so, and Microsoft believes so as well. And it's just freaking fun to use!