I was 15 when this album was released, and luck would have it that my next door neighbor's older brother, who was 20 at the time, he and his friends were Clash fanatics, and this album was all the rage with them, and is why I was exposed to it a ton during a time that I might not have ordinarily been aware of it due to only radio exposure, and by me at the time mostly following stuff like Foreigner, Boston, Heart, Steve Miller, The Cars etc...
They were all Covington Latin graduates, and it would stand to reason that when letting off their party rockin' steam at this time in their above average intelligence lives that they would gravitate to edgy non-mainstream music, and so underground alternative and punk (Way before it was cool) was what they turned to.
The Clash, The Ramones, The Talking Heads, The B 52's, The Pretenders, Blondie, Cheap Trick, The Sex Pistols, Elvis Costello, The Boomtown Rats, The Violent Femmes, Echo & The Bunnymen to name a few.
He and his group of friends even went on a trip to Germany to see The Clash, Cheap Trick, and The Cars. At 15 I was as spellbound and envious as you can imagine.
Honesty because of them, they set me on a path way beyond the radio, because they helped to make me aware that there was so much more out there to be discovered.
I didn't go on to be a complete Clash fanatic myself, but "London Calling" would no doubt be the one that I would turn to if needing a dose, and more so than that it just simply represents for me the dawn of musical discovery outside of the mainstream.