25 years in, the list has been resorted & modified many times over. I'll try to boil it down to the big ones:
- Hearing a Tannoy dual-concentric speaker for the 1st time at Audio Atlanta (now long gone). It was just the modest Eyris DC3 model, but blew me away with the coherence and imaging versus more conventional driver arrangements. I've been exclusively Tannoy speaker'd for years now with no inclinations to change.
- My first vinyl setup (SOTA Star III w/ Benz Glider). Spanked the Meridian G08 and Sony SCD-1 I had at the time. Game over for digital here, for years. Vinyl still dominates as my primary source today.
- Hearing my first Koetsu cartridge - a well worn vintage Onyx. The king of romantic, fun MC sound and a polar opposite to the modern high-tech Ortofon MCs I was using at the time. I thought Koetsus were stupid (pricing, several models differing by nothing but stone body) before this. Never thought that again, and started a collection.
- Hearing Stax SR-009 electrostatic headphones on a very high end DIY T2 amplifier. Next-level headphone sound. Converted me to e-stats (for headphones). Dynamic and planar driver headphones have had a rough time with me ever since.