The best I've ever owned are my current Audio Physic Avanti III. They're really quite special speakers that doesn't draw attention to anything, just sounds very organic and live. Never heard a speaker that can complete disappear like the AP's.
Before then, Thiel CS2.4 (still awesome speakers), Magnepan 1.6, Hales Concept 5, Magnepan MMG, customer built speakers (small standmounts with a matrix birch, viscoelastic glue, HDF cabinet and all ScanSpeak drivers). First real speakers were Dali (forgot the model now, but I worked the entire summer to afford them).
Before then, Thiel CS2.4 (still awesome speakers), Magnepan 1.6, Hales Concept 5, Magnepan MMG, customer built speakers (small standmounts with a matrix birch, viscoelastic glue, HDF cabinet and all ScanSpeak drivers). First real speakers were Dali (forgot the model now, but I worked the entire summer to afford them).