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
Probably my Audire Diffet 3 preamps, which were very limited production.  I have only ever seen 5 for sale, two of which I bought and one the ad for the one I sold.  I know of two others.  Julius also made a dual mono preamp with tone controls, the  Andante, because he did not use the superstitious Japanese number 4.   (His fourth amp was the Forte.)    I still kick myself for not getting the one I saw advertised.  It has two circuit boards, one above the other, with separate controls for each channel.  Even rarer is a Diffet 5, of  which a half dozen were built to go with his tower amps, with open bottoms for air circulation.  At last report, his phono amp is still used by a Stereo Review tester in his number 1 system.  My Diffet 2 is really good, a bit better than my Bryston, but the 3 is as good as I will ever need, and I tried a lot of them.
  • My favorits are Jadis JA30 monos from 1997. Latest ”uppgrade” are new power tubes KT120 from Shungyang, very pleased and closest you can get to NOS.
  • Also have KT88 from Shungyang but changed to KT120 for it’s bigger ”soundstage”. 
  • I also have to thank (deceased) Bobby Palkovic for his strong dedication and belief in Merlin speaker. I have VSM-X with uppgrades on filter and internal cabling, recently I added a 10 nF from Duelund on treble and mid/woofer section, it opened the top on each f-range spot-on.

Regards,
Clabe
My fave pieces are a pair of B&W 805Ss connected to a Creek 4330 integrated. I've had the Creek for over twenty years and I haven't heard anything like it since, even the (optional) phono stage is mega, quite an achievement for its size and price. The B&Ws are newer, about 10 years old and I can't see parting with them either. I compared them with a pair of KEF LS50s a while back (based on all the gee whiz reviews) and IMHO the B&Ws handily blew them away!  
Krell KAV 300r. It has a great tuner, and adds just the right bass to the speakers paired with it. For me it’s a keeper.