Though I don't completely discount the idea of complimentary synergy, I too tend towards what I once read Jahn call "additive" synergy. My 840C > 840A > Quad 12L is a great example of this, with a super clean sound from top to bottom, and a cool but liquid midrange with good treble extension in all three components.
Also, the way you organize your records looks kind of like the way I organize mine in the extra bedroom, which has become the "throw all your audio crap in here" room.