The whole soundstage thing is something I find fascinating.
People seem to forget (although it was mentioned earlier in the thread) that the whole thing is an illusion and as such is open to the interpretation of the listener, I personally am unable (regardless of the system or recording) to hear what is referred to as depth or 3D in a soundstage, I get the "speakers disappearing" thing but have never been able to place an instrument for hear anything coming from behind the speakers.
Interestingly I have challenged people on several forums to name a piece of music and explain where a particular instrument appears to be, then see if others agree, as yet only a couple of people have done so but nobody has been able to confirm that they hear the same.
Marantz CD63 KI Signature
Project Debut II
Pioneer A656 Reference
Epos M5s
Atacama Stands
Maplin speaker cable cos I can't hear a difference
Various interconnects as above