Leap Motion - no touch touchscreen
This seems to solve the problem of fingerprints on your monitor, but I don't know how fast response time can be.
The response and accuracy is pretty good. It can track all fingers on both of your hands separately and even give you a vector of each finger or a sphere angles of your hands.
Comparison with touchscreen should not be made, this device is more like a Kinect, it uses pretty much the same principe but instead of full body motion it tracks fingers. As kinect, it doesn't give the 1:1 feedback as touch screen neither it gives any barrier feedback in z direction..(you "clicking" in mid air)
There are few obvious applications - one would be 3d modelling where you could rotate or perhaps even somehow edit the object with your hand in the air. Other could be games (fruit ninja) - but on most games this could be a novelty that wears quickly off - it isn't fun to play a game too long with your hand in the air.
I think the Leap will all shine or fall on the supported applications. There is practically no desktop application where moving the finger in mid-air would give you anything better or even equal to mouse or touch screen (think of controlling your mac or windows desktop with Kinect).
So it becomes a solution that desperately needs to find a problem. It is non expensive and cute, but as many similar items you would need to find a reason to keep it plugged in a computer week after you buy it.