Totally agree here.
Apple has it right regarding screens that sit up away from you - people would rather use a trackpad on their desk, a mouse and a keyboard to interact with the screen. It's uncomfortable, awkward and tiring to reach up and press things and drag things around a touch screen that's horizontal.
For something on your lap vertically, or where it's on a table vertically, like tablets are used, touch screens are great, because there is no room for a keyboard or mouse. The screen IS the keyboard and mouse together.
If you already have those, I see it as such a waste. Everyone I've talked to that's had a PC with a touch screen (along with a keyboard and mouse), loved it for the first couple of days, but don't use it anymore as it felt just like a gimmick. Sure, occasionally, they feel like they want to touch something on the screen if it's on a web page with a big font and big buttons. But for daily activity, they don't. 95% of what they do on a laptop is too small and too precise for a finger to really work. And you need a keyboard anyways, so why not just have some input device next to the keyboard, or a part of the keyboard, so you don't have to keep moving your hands up to the screen.
For a tablet, awesome, for a laptop not so much.