I was thinking about to buy a 19" LCD Display when I found a website with a pretty cool display. It's the Helio Display from IO2 Technology.
Heliodisplay images are not holographic although they are free-space, employing a rear projection system in which images are captured onto a nearly invisible plane of transformed air. The projected images are two-dimensional but appear 3D since there is no physical depth reference.
Here it is a Heliodisplay's picture
I think I will have to save a bit more to buy one of this :).