In St. Louis in the 1970's, it was Peaches Records & Tapes. There were some mall stores too, but Peaches stores seemed huge at the time; the two locations I remember best were both former neighborhood supermarkets in south city at Hampton & Chippewa and in north county on West Florissant at Chambers Road. They weren't as big as supermarkets are today, but even those smaller former food stores were big for record stores. I don't remember everything I bought there, but I think I got The Beatles At The Hollywood Bowl at West Florissant, and Chubby Checker's Greatest Hits and The Jan & Dean Anthology Album at Hampton, among others. (Why do I remember this 40 years hence?) And have you seen the prices on a used Peaches record storage crate?? They're still in high demand, when you can find one.
These days, it's Record Exchange on Hampton at Eichelberger. They've moved several times, but they've been around since the late 1970's too. There are some other used record stores, but RE is bigger, it's in a former library building. Not that I haven't visited other used outlets, just not nearly as often. But there's still nothing quite like breaking the cellophane on a fresh LP, the smell of the ink and the shiny finish on the jacket, handling the disc for the first time--couldn't wait to go to Peaches, then couldn't wait to get back home to start scratching up the new acquisition right away. (As a kid, I didn't have 'turntables', I had 'record players'. The difference is still audible on those LP's that did time on the 'record players'.)