The basic hologram. A simple 3-D image that provides either a 3/4th view or a complete image that you can walk around in its more advanced mode.
A step above the still image, it still does not always offer a complete image, but it is a moving image. Often used for communications, video panels, and entertainment.
A Stable Moving image is an interesting variation of the normal Moving Image. It is an independent moving image of a single object (like a person) projected through an emitter powerful enough to cause the image to generate its own surface tension. This makes the image appear ultra real, and indistinguishable from the real thing. However if the surface tension is broken by anything, such as someone touching the image, then the hologram will totally break down and dissolve.
Again, this is just a step above "moving images." It is a room that provides a full holographic environment. The viewer still cannot touch the holograms but the illusion will be so real that he feels that he can.
The introduction of props can make the illusion so real that the viewer can be convinced that he is in a real environment.
Often used for therapy, and entertainment.
This is a step above the "moving image" or the "holo-room" because it enables the viewer to "feel" the holograms. It is really not an advancement in the hologram, as much as it is a support tool for it.
The viewer wears a suit that is linked to the holograms and keeps track of where you are and where they are suppose to be... When the viewer is touching or is touched by the hologram the suit responds giving the illusion that the viewer is interacting with the hologram.
Often used for therapy and entertainment.
This is the ultimate Holo-room. It is more than a simple hologram projection studio, it also contains replication devices and force fields. Instead of wearing a suit as in "interactive holograms" the viewer actually feels the holograms, either because he is touching an actual thing (provided by the rooms replication devices) or because he is touching a force field that is occupying the same space as the hologram. An advanced system can also deceive a viewers perception (make them walk in a curve while they think they are walking a straight line) to make a confined area seem like a vast one.
Often used for therapy, entertainment, black ops, and for training purposes.
VR are artificial realities created within a computer, instead of outside one with holograms. The viewer either interacts with them via special goggles and gloves (and sometimes with a suit like the ones in "interactive holograms"), or they have gotten a computer jack implant so that they interact with the computer directly from the brain.