For me it was the original AR-XA turntable along with a Dynaco SCA-35 integrated amp back in 1974. I was using a pair of homemade speakers built by my older EE brother at the time. Among speakers, after going through a number of ARs, Altec's, EPIs and such, it was getting a used pair of Spendor BC-1s which I acquired around 1993-4. What a revelation - that magnificent midrange! They stayed in my main system until about 2011.
Your first component that was "special"
I got into hifi 40 years ago. I had a Pioneer receiver, Kenwood table, various entry level cartridges (ADC, Stanton, Empire) and Studio Design speakers. I wound up buying a Shure V15 Type 3 cartridge. That was the first piece of gear I bought that was way beyond ordinary. I had kept the cartridge until about 2o years ago- I sold it because by then no decent replacement stylus was available. Wish I still had it.