My vote goes to GR-Research Alphas (think of a speaker similar to Pipedreams). I know of no other speaker that will come close to doing what the Alphas will do in terms of freedom from congestion, soundstage height, scale of dynamics and output or integration between drivers (anywhere near your $7k price point new or used). This design has many of the same attributes that the Pipedream's design has due to the multiple high performance drivers not being pushed anywhere near their limits and it being a simple two way design (which is MUCH easier to perfect than a three or four way design).
IMHO GR's speaker designer (Danny Richie) is a VERY seasoned, has a great ear and only uses the "best of the best" crossover parts in his Alpha design. I've looked at the inside guts of many of the well known big buck speakers only to be completely disgusted at the parts used in their crossovers! In fact, a couple of the speaker suggestions by other posters here can be improved with just a $100 of upgraded parts in their crossovers too! (i.e. those speakers were not designed with a "use the best crossover components" mentality- argh!). IMHO GR Research's Alphas are more refined than a pair of the big $75k+ Pipedreams!!
IMHO GR's speaker designer (Danny Richie) is a VERY seasoned, has a great ear and only uses the "best of the best" crossover parts in his Alpha design. I've looked at the inside guts of many of the well known big buck speakers only to be completely disgusted at the parts used in their crossovers! In fact, a couple of the speaker suggestions by other posters here can be improved with just a $100 of upgraded parts in their crossovers too! (i.e. those speakers were not designed with a "use the best crossover components" mentality- argh!). IMHO GR Research's Alphas are more refined than a pair of the big $75k+ Pipedreams!!