Speakers known for great midrange.

I'll have to throw another plug for Dynaudio. In all my years of listening/owning different brands I have not found any other speaker that can compete with the Danes, especially in the mids...

Two of the best sounding set ups I've had were using Pass (an XP 10 pre and a 250.8 amp) with Harbeth. I had the 30.2 which were great - very detailed and neutral and uncannily good with voices- and then upgraded to the HLS5 Super which were amazing- really really musical and more involving, loved them. 

IMHO ATC. Harbeth and Spendor sound colored by comparison.

For the OP, ATC probably won't work if a syrupy coloration is what one is looking for.

Celestion sl6si if you can find a pair in good shape. Otherwise Wharfedale Linton or Harbeth ps3

I thought Vandersteen midrange was the best until I heard Tektons. Tekton are the best I've heard. Get the Moabs for 5k.