Depends what you do with it obviously. Lighting software like Chamsys or Grand MA screams for touchscreen. For work I also need a Mac, and I stupidly hit the screen all the time.

If you're not into graphics / art design enough to have a separate wacom tablet, again it is useful in a pinch.

There's no "it's good!" no "it's bad!", it is just a matter of how useful it is for you. I don't know on windows, but with Gnome touchscreens work very well.