Some good responses so far and some interesting ones too!
I recently moved and was faced with downsizing my equipment.
A few pieces I decided to hold on to even though it's no longer in use are:
Audio Valve Eclipse pre and Challenger mono amps: The Eclipse preamp chassis is made of stainless steel (similar to Shindo) and weighs over 40 lbs. It sounds amazing, very quiet, and has one of the best bass of any tube pre I've heard. This is a German brand that never sold well in the U.S. despite having prices that I consider low for their level of quality. With the recent passing of their owner, Helmut, the company has gone with him.
vintage Studer A-810 reel to reel: this is a highly regarded tape machine that I was able to obtain from a home studio, it's in excellent condition with original box and packaging (rare to see). Went through so much trouble to get the old electronics inside overhauled that I don't see ever letting it go.