This is an excellent thread.
The first hint for me was in the 60s, playing records on the family Magnavox console. Glenn Miller, Pete Fountain, etc. Then with my first earnings as a teenager I bought a Dual turntable and a small Marantz receiver. The first speakers were also Marantz, but were soon traded in for a pair of Epicure 100s. That might be the gateway right there. The Epicures had an interesting tweeter.
Thinking about it, the next fully confirming gateway hardware was the next change of speakers to Infinity Kappa 8, with an EMIT tweeter. I tried stacking the Epicures on top of Advent 6003s, but that didn't work so well.
My dad sold Advent as one of his lines for a while. I still have a pair of Maestros, as back speakers for an AV system that I am not at all passionate about.