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

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.  

Forte IIs, my wife didn't like the looks.

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.

Sold Marantz scope tuner to cheap.
Don't want it back.