to-Hmmm…looking over the things about gorilla arm and the like, I have to say…
My ultimate setup would be a touchscreen monitor mounted on one of these arms, with a desktop build (so I would have an external keyboard+mouse). When I’m using my keyboard and mouse, the monitor would be on my desk shelf thing so I could use it as a regular monitor. When I need it to do touchscreen things (Photoshop, other art things), I could bring the monitor down to desk-level and tweak it at a 45° angle, to use more comfortably.
(Running Mac OS X, so it would be a hackintosh. (￣ω￣;) But I guess Windows 8’s Metro UI would actually work pretty decently in this case. :O)
As for the touchscreen vs. non-touchscreen, it seems…
I actually find touchscreens a little easier/natural to use. I don’t have to wave the mouse around, trying to figure out where the cursor is. I don’t have to have my hand in a weird, semi-curled position. There are people who go “nonono, touchscreens are a lot more work”. Of course, they’re more work if you’re trying to stab a tiny area with your finger and keep mistapping (normal-to-big sized fingers do not go well with small hit…box…things…).
(Touchscreen keyboards on the other hand…but if I was just using a touchscreen MONITOR, I wouldn’t have to worry about a TS keyboard, because I would need to use my analog keyboard! :P)
But seriously. YMMV.