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

After many years  in audio and going through so much equipment, I can't say I miss any particular piece of equipment. My present setup is best I've had, I expect future changes will also be upgrades. At this point in my audio evolution I find I'm no longer nostalgic over past components.

If I was to wax nostalgic about any one particular piece, it would probably be recalling the experience of hearing my CJ MV55 tube amp after many years of exclusively running SS amps. Twenty some years later, tube amps only for me. Also, still own the CJ amp, likely will never be used again as Its bettered by all my present tube amps.

My favorite is my 833A single ended triode stereo monoblocks. I could never afford to buy manufactured ones ($350,000 for WAVAC and a "cheap $60,000 made in Poland.) I built my own with all the design features I want and could not count on getting if I could afford one from a manufacturer: polypropylene power supply filter capacitors in a pi network with the chokes on the negative side for grounding safety instead of inferior electrolytic caps, Hammond 1642SE output transformers good for 4kV carrying only 1kV at which by battery polarity reversal tests on the zero bias grid shows the same current change from the modest 20 ma plate current so I know it s respectably linear and which sounds spectacular, The Hammond transformer is good for 300 ma. This is a marriage made in Heaven for Magnepan speakers which are more than loud enough running the tubes so modestly and allow that SET sound without the need for complicated cones, cabinets, and crossover networks that are sensitive enough for less powerful tubes such as the 300B or the 45. I drive the 833A grids through Lundahl transformers with 45s and these with choke loaded mu follower 2C22s directly with no need for capacitors n the signal path. It took me over two years to perfect this system and I desire no other.

1. Plinius SA100mk3 amplifier upgraded by Vince Galbo's Ralph Abramo near San Berdoo CA (pliniusaudiorepairs.com).
2. Companion Plinius M16 pre with designer voodoo (Gary Morrison)

These form the soul of driving Dynaudio C1 Sigs.
TT and digital under serious review....

Got JAZZ???

HK 150 wpc integrated amp circa late ‘80s early 90s capable of +/- 80 amps instantaneous current. A real brute for then something shy of $900; Wall to Wall Sound if you’re old enough to recall and not to old to forget ;). Wish I still had it. Attempted one costly repair that didn’t last and moved on. Might have tried again if I would have considered dragging around a 40lb paperweight.  

Interesting seems as if mostly everyone’s favs are from yesteryear and not today’s new, improved, and much more costly.

Pair of big Vandersteen 4 speakers from mid-'80s. Bought them used; they arrived on a semi-trailer that was too big to get in the driveway. Had to walk them 200 ft to the house w/dollies. 

These have built in subs, each one = 2 X 12" woofers connected via steel bar in push/pull configuration. The very flexible tri-wire system allowed use of SS on the subs & tubes on mids/treble, which is what I did.

They're still the finest sound I ever heard from speakers. And they're still stored in a closet here in our 2nd house (moved in 1991, nowhere to put that big audio system).