Everyday from Buddy Holly and the Crickets.
Totally stripped down in its original format. As I got older, I realized that I was always drawn to very unique or different sounds in music. Things like unique instruments or unique vocal arrangements will always capture my attention.
Although it isn't the first song I can remember hearing, it's significant because it was a song I really loved on the very first Cassette Tape I ever bought with my own money. Honestly, about five times through listening through it and I had the words down and would sing along.
For some reason buying my first cassette tape sticks out in my head because I bought it through a fund-raiser that my grade school, Fairview Elementary (now closed), was having. I was in 5th Grade, Miss June Coradetti's class and it was Spring of 1977.