I've never heard a large system integrate everything in a natural way. They always seem to foul up the bass to my ears. Live bass is much faster than most of those big drivers produce it. I have no best but consider the following very memorable in their own way:
Apogee Stage and Scintilla (the most transparent speakers I have ever listened to)
Quad ESL-63- First time I heard them I was absolutely smitten. They still have a midrange to die for and if I were to have a 2nd system it would be based around them.
SoundLab A3 I haven't heard the big boys but I can imagine, wonderfully coherent as Albert notes but not too dynamic, damn what a shame because they do everything right, I do believe the big Soundlab might be "The last speaker you'll ever own".
IRS Beta's (except for that damn bass the rest was superb)
Merlin Millinium OK so I'm prejudiced because I own them, but I LOVE their coherence and their point source nature, I can't hear the drivers crossover and this is very important. They don't have wall shaking bass but what there is is very clean, quick and natural. They fill up a room with music without bringing attention to themselves, they just disappear. They are tonally neutral and have a liveness and an immediacy that I'll never tire of. Lastly, they have a size that is easy to live with. I would qualify them as without a shadow of a doubt the best two-way speaker I ever heard, sorry Wilson.
