Underappreciated components.

I've had Sunfire Symphonic Reference stack amp and pre.
The amp is really underestimated component that has an ability to bring to life toughest speakers. There's no limit on load to drive weather it's very low or too high. It's load-invariant amp.
To me it's one of the best products built by Bob Carver.
The preamp I've replaced with Classe 30 which gave me a substantial improvement in both analogue and digital playback plus balanced in/outs.

Judging by the used prices I would say Alon I thru V speakers ... very open sounding speakers with excellent bass extension

Bill Woods Horns.

I bought a pair of speakers for a girlfriend after auditioning a bunch of speakers at an electronic store and these were so good I took them home and hooked them up to pretty expensive components, they are so good they deserved it. The speakers are JBL venue series arena. I bought extra pairs for myself to experiment with.
For the money $100~ used they outdo many that cost more.
They make a great gift as an intro to audiophile sound.

I believe VPI is underrated