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

My VTL 450MKII Amps.  They are the best amp's I ever owned.  Before the 450's, I used VTL 300 Deluxe MB's for many years.  Owning the 300's gave me an opportunity to get to know the folks a VTL very well due to repairs and upgrades.  The 450 have been trouble free since I got them 10 years ago.  Since buying the 450's I've talked to VTL twice, a quick question over the phone and at CES.  I purchased both pairs of VTL amps used, I could never afford new ones.  VTL has always treated me as a valued customer. 

My favorite: Thiel CS2.2 amber wood speakers. My first true audiophile purchase in the 90's. I enjoyed listening to them for decades.  Amps, pre-amps, and sources came and went, but the Thiel CS2.2 speakers were a constant. Just traded them in for about $500 less than I paid ~30 years ago. $500 / 30 years < penny per day listening cost.

I upgraded to Thiel CS7.2 speakers, so no regrets.

Fisher 500C Vintage Tube Receiver. Two on the shelf.

Anytime I need to change, sell, fix tuner, preamp or amp, this baby comes out of retirement, keeps the system truly enjoyable until ____ is back in town.

Pair of Vintage Fisher 80Z mono tube amps, pair and a spare on the shelf. Not going anywhere.

my efficient speakers, I never needed anything more than 30 wpc, could probably go lower, just never tried.

ATC SCM100ASLT loudspeakers. Listening to them right now.

The oldest unit I have is Sony CD707ESD
purchased 1990 still use with Schiit Bifrost 2 DAC.
The second oldest is Mondial Designs
Aragon 8008BB amplifier purchased in 1996 still in use with some tweaks love it.