What's the best and/or favorite piece of equipment you've owned? And do you still own it?


My favorite piece(s)  are  (and I still own them) the Martin Logan Ethos lousdpeakers and Soudsmith Paua cartridge.  As far as speakers go, electrostats are my favorite and will replace them with another set of electrostats.  I'm currently eyeing MUR Audio SP1's.  These two pieces make my rig sound great.  
polkalover
Bought mint used Infinity IRS Beta’s over twenty years ago.  They are still mint and will never sell them unless someone wants to downsize from their IRS V’s.   Wish my hearing was improving, not declining.   
My favorite is a pair of horn-loaded 3-way speakers from the 1960s that were my Dads. University "Dean". They are huge and heavy and super-efficient (103 dB at 1 watt at 1 m). I have them at a vacation home and am always blown away by how great they sound. Big live, natural sound. You can feel the air movement when they are cranked. This system rivals my main system that costs 15 times as much. Unfortunately, I will have to sell them soon as we are downsizing, let me know if you are interested.

My biggest regret was selling a Sansui  777 integrated amplifier back in college. I have yet to see another one. 
Woodsong Garrard 301 wt Triplaner arm and Miyajima Shalabi cartridge. The beauty of it and the function always thrill me. Not to mention its drive and impact. Never had another TT that recreated music with such reality. And I just love to look at it doing its thing!
15 year old Magnepan 20.1s, originally $12,500, bought for $5,500 right here on Audiogon. Magnificent sound.