Sugarbrie's right about the room and electronics playing a big part. If those are right, the best I've heard at disappearing are the Pipedreams, the Avalons, the Audio Physics, the mbl 101s and my speakers (Sforzando JL-1s, not currently marketed). With the Pipes and the latter two, you can sit well off axis and "see" the performers as though you were off to the side at a concert, or even walk between and behind the speakers right into the soundstage.
Which speakers do the hologram thing?
Some reviewers talk about how speakers can produce a 3-D image so convincing that it seems one can "walk amongst the performers" or "sense the air between performers," or they may say how "each musician appears to occupy a solid space," etc. I'm not certain I have heard this. In your experience which spekers have this ability?