I discovered part of it when I was 10 and it made the profoundest impression on me. The grand ball theme, "Montagues and Capulets" (see clip below), was used as the signature tune to a serialised adaptation of Alexandre Dumas' The Black Tulip, starring a youthful Simon Ward and Tessa Wyatt. I loved the drama, but most of all I was completely swept away by the grandeur of the music, while having absolutely no idea that it was something well-known, with a life of its own outside weekend tea-time telly.
When, a few years later, it was played in class by my music teacher and identified, I rushed out and bought the Classics For Pleasure LP version of the ballet suite, which rubbed shoulders uneasily in my prized record collection with Davids Cassidy and Essex. It has certainly outlasted both of those in my affections!
Was ever there a more searingly passionate and intense musical evocation of love? - its darkly dangerous, elemental aspects a constant undercurrent beneath the heady joy and wonder. I don't think so. (Carlos Acosta and Tamara Rojo are sublime in this version (skip the 2-min intro and cut straight to the Love!))
Actually, the reason I started musing on this particular topic was to wonder how often these days does routine telly-gawping introduce children to classical music which makes such an impression that it stays with them for the rest of their lives? I can't think of any. Can you?
Here's another unforgettable classic from the 1970s - the Adagio from Spartacus by Khachaturian, immortalised for ever in The Onedin Line:
(Which also, incidentally, included bits of Vaughan Williams's Fifth Symphony, de Falla's The Three-Cornered Hat and Shostakovich's First Symphony during the course of the action. Now there's something you don't get in the average episode of Doctor Who or Casualty.)