Best

NAD 3020. Not the ultimate amp but when it came out many years ago it was a revelation. Sound that surpassed anything close to its price (under $200). This amp relieved much frustration for those of us who could not afford real high end. Without products like this hi-fi would die. Thankyou NAD.

Magnepan MMG, at $500 a pair. MIT Terminator 3 speaker cable closed out at $65/pair in second (or Terminator 2, "for a few dollars more"). Audio Alchemy DLC linestage preamp a close third, at $225 (before they went away). ASC Frescoe Traps in fourth (before they were replaced by something a little bigger and pricier). Kimber 8TC rounds out the top 5, in my opinion (not recommended for systems having even a slightly forward presence region, however. It's a "quickish" sounding copper cable with a large enough cross sectional area to let the dynamic swings of a beefy system come through...lacks tonal refinement of pricier cables, and also that of the much cheaper MIT, in the right system context, of course).

Rogue products.

The best "Giant Killer"...is actually the reference point that had much to do with the "High-End" even existing...the original Large Advent Speaker....others would be, the current Magnepan MG 1.6QR, the Kimber Silver Streak cable.. ...and, perhaps, the original AR turntable...I wonder how many are still in use?

Used Dynaco Stereo 70 amp. For 20 years they sold for around $100 and were more lisenable that the 1,000's of amps, intergrateds and receivers that have come and gone.