Belgium based Holocube offers an interesting looking holographic display.

The Holocube projects an animated 3D image inside of it's housing. You can view the 3D scenery only from the front of the box. The 20 inch sized Holocube has an integrated HDD that stores the video for the projection at a resolution of 1080i.
The company positions the Holocube as a product display for businesses.
More details on Engadget and on the Holocube site.

Another large scale holographic display system we reported about in 2006 is the Vizoo Cheoptics360 XL. This holographic display can be viewed from all sides and is life size.
In 2004 we reported about Provision that offers POS systems with floating holographic displays.
IO2 Technology showed their Heliodisplay in 2003. The company is still offering holographic display solutions.
If you have the money, there are holographic display solutions available today. There are limitations to each system. The Star Trek Holodeck has not been invented yet.