Maybe I'm the new kid without being in the know (I haven't gotten to listen to most of the previous speakers recommended, but nonetheless here is my 2 cents: Kef Reference Four Model Two. They meet all of your criteria, and are gorgeous. I wish I had the extra 2 grand to purchase them when I bought my SL-3's (which I adore). A local dealer played the "dark side of the moon" and I was hooked, it was like a religious experience. I didn't know "traditional" speakers could sound that good.
Which Speaker in the 4-6K Range?
I am interested in buying a pair of full range floor standing speakers that have the following attributes:(1)Sensitivity of 90db or greater. (2)Bass extension down to at least 25-30hz. (3) Solid built quality. (4) Ability to simply diappear and (5) cost about 4-6k. I am considering the Silverline audio Sonata and Coincident Technologies. I prefer the Hales Design Group Trancendence 8 but it costs 10k unfortunately. Please help.