Which speakers do the hologram thing?

I would concentrate on speaker placement and room accoustics more than the brand of speaker.

And I agree the electronics matter also. (What happened to the edit function Agon??)

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.

Spica Angelus are imaging champs and pretty easy to set up, just don't get carried away with the gain knob on your preamp (I blew the woofers on my Angelus'during a party). Celestion 700's did a credible job as well, but in general I found "box" style speakers just aren't up to the task. In my experience the most holographic speakers are planars; I've owned Apogee Duettas followed by Martin Logan Quests and Aerius (the Quests are in my main system, the Aerius in my home office system) have been wonderful transducers. Planars are the way to go, but, be ready to invest a LOT of time moving them around in the room til you get the placement just right. Once you set up planars properly you'll never be able to go back to sealed box speakers for critical listening again. I've always used pretty good electronics so I really haven't noticed associated gear making a huge difference with planars (I'm referring to imaging only, of course any change in gear will be heard). Your choice of speaker wire will make the biggest difference with planars, experimentation is necessary. YMMV

What Sean has heard with the AvantGardes, I've heard with the A-Capellas, which are also modern horn loaded speakers. I see his point about dipoles, radiating out of phase towards the back wall. However, when you listen to live music in a room or hall, you never just have sound reaching your ears in phase, having all sorts of reflections from everywhere in the listening area. This is probably one of the reasons, why a well set up pair of dipoles in a carefully treated listening room can sound uncanningly real, more real in fact, than the A-capellas, which though beautifully holographic, will sound just a tad too "pure", ethereal, speak artificial, compared to say Sound Labs or Quads. Though more holographic, they cannot really sound "dirty" like live music and dipoles often do.