What speaker is the most musical, one you never want to sell?

Oops that is NSMT..

Every Magnepan I've ever owned? I've enjoyed other speakers, and in the short-run even been quite impressed, but once accustomed it is awfully hard to give up whatever the magic is they bring. 

Quad 57s.  Modified by me ages ago.  Regardless of their shortcomings, I need to come back to them occasionally because they do Real better than anything that I've heard.

I built my GR Research NX-Oticas five years ago, and I've never heard better, at any show or home. Keepers for sure. Assembly takes some time, but it's not difficult, with hand tools and six clamps. They sound best with some room treatment. I also like Acora Acoustics, Rockport, Joseph Audio, Borreson, and Raidho, but no reason to spend that much. Audiogon is fun...some excellent writing  and expertise here.

 a pair of JBL century L100's  with the 123a drivers, when you open them up the driver dances like no other , and I can hear them booming bass  and crisp and clear highs  40 acres away on the ranch.