Two wildly different speakers certainly meet the "best disappearing" category for me: the new Martin-Logan Prodigy, and Richard Sequerra's MET-7 mini-monitor. I've never owned the M-L Prodigy, but I did have a set of MET-7's for a number of years. MET-7 threw a phenomenal soundstage, imaged like crazy, and usually "weren't there".
