What piece(s) of gear did you sell/give away that you would like to have back?


We've all done it - sold or traded a piece of gear we had fallen out of love with, then regretted that decision at some point. If you could go back in time, but could only retrieve one piece, what would that be?
discnik
Precision Fidelity C7 tube phono stage. Designed by Bruce Moore (MFA and Paragon). Advanced cascode circuit design using 12AX7's. A pair of potentiometers and a selector switch on the front so it can be connected directly to an amp. Bought it new for $500 from American Audiophile on 61st and Madison, NYC in '79. Stupidly sold it a few years later for half-price for some fast cash!
My first pair of Quad 57's, which I had in use from '81 to 2000 - 19 years! Again a stupid sale when I needed some fast cash!
I bet the introduction of CDs in the early 80s had some influence on your decision to sell the Precision Fidelity phonostage, roberjerman? That sounds like it was a very nice unit. $500 seems like a pittance these days, but it was big money in 1979.
2016 My stored system got nicked.. C22, 2 MC240, TT, SS Amp, 3 way  tube crossover, a footlocker of OLD valves, on and on, and on.. 

I wish I wouldn't have sold them to the insurance company, BUT I didn't have a choice, at the time.. 43K in insurance and I'm still hunting up parts.

Could have been worse, no insurance or no replacement value..

Regards
Sellers remorse? Nah man, alien concept. If it's worth keeping why would I sell it? Unless hard up for cash, which to me would be such a painful lesson it would never be repeated ever again. Like the one time I had a Yamaha RD-350 and a Datsun 240Z and after college I was broke and sold the Yamaha for like $800.

Then 20 years later Motorcycle has an article on vintage bikes and there is my exact RD-350 same color and everything only now worth ten grand!?! WTF!??!   

Learned that lesson. Still have my 1979 911 SC. Now worth twice what I paid for it. More than twice. Shop critically, buy wisely, sell rarely. Only way to go. 
I regret selling my Odyssey Stratos Extreme and the Kismet Reference floorstanding speakers.  Only got rid of them because my wife was on my case to get rid of some of my treasures.  I had 4 or 5 amps and 3 pairs of large speakers hanging around. Got rid of all of them, should have kept what I mentioned above.  The Stratos would have been a great back up amp and the speakers were really quite special.  
I regret selling my Spendor SP 100 Speakers. I loved them, but got the itch, as well as being younger and not as wise.
They were more colored in some ways than my current speakers, but it's all about enjoyment and involvement, and for that they were hard to beat.
Although I like my current speakers better, to me it's like different flavors of ice cream, and it would just be nice to have them around to use once in a while.  
JM lab Mini Utopias. I’m not sure why I got rid of them in the first place. Just the hope for more better I guess. But what is funny is thinking about the old great stuff I had in the beginning only to be disappointed when hearing it again. That’s happened on a few occasions.
Mint SAEC 407/23 tonearm. Gave it to a friend.

Mint TD125 MKII w/SME 3009 arm. Same, gave it to a friend.
My Tannoy Dual Gold 12 inches.... But they dont fit on my desk here and even in my next room when i will sell my house...

Happily it is not so much only the speakers quality that count, but the room where they are immersed like a whale in the sea...

Acoustical embeddings active and passive controls and material passive treatment weigh sometimes even more and at least weigh on par with the level of speakers design quality, i suppose  here that the speakers are not bad one sure...

Then my actual Mission Cyrus 781, a very good speaker but a notch under Tannoy, gives me tough a better sound than my Tannoy years ago, not because they are better like i said, but because they are rightly embedded acoustically, mechanically, and electrically....

The room is ALWAYS more powerful than any speaker and at the end always win....
Sold my Denon AU S-1 SUT year's ago! Been kicking myself for that bonehead move! 
Micro-sieke DD-40 TT with MA-505 arm. The most beautiful TT you ever saw. Solid rosewood base. Look it up online and check it out. Sold it for next-to-nothing 20 years ago because I thought vinyl was dead. Also sold about a thousand LP's for, I think, maybe a hundred bucks. Pretty dumb, you say?  Yes, it was.
Maybe these sales/gifts of favorite items led to good stereo karma in return?Anything occur afterwards that went in your favor which you didn't expect?