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

Very fond of a pair of LXmini's I DIY'd last year - inspiring the sale of Tekton DI w/factory upgrade, and they outshine the ML's, B&W's and GE's (floor-standers still have in the stable). Others just can't compete - they all just sound like speakers to me now, while LXmini's disappear and sound real. However, I have not heard many other speakers that might compare favorably in this arena (Spatial, Project, GR-R, etc.). LXmini's do require subs for full-range. ML e-stats share some likeness, but have such a narrow sweet spot. I'll probably always keep a pair of LXmini's (these, or future builds).

Revox B77 and I still have since 1972. It was serviced every few years and still works flawlessly.

Best: Philips 22AR470

Favorite: Rotel RA-414 tie with Technics SL-Q2

I still use Technics SL-Q2 and, just in case, did buy an identical one a couple of weeks ago. Spare, NOS (!?) stylus arrived today for the first one.

Adcom GFA- 585 LE with my 93 Khorns in Germany...gone....I'm going to cry now.... 

Without a doubt it was my McIntosh Power Controller.  I couldn't believe what a difference it made.  Don't expect I will ever get rid of that thing, unless there is no room for it in the retirement home.