I bought Metallica's ReLoad album and it blew me away (until then, the only other music I had listened to was hip-hop and radio music). Then I was a Metallica fanboy for a year or so and bought all their albums. Little did I know I had barely scratched the surface of heavy metal.
I wanted to find other metal bands, and checked out stuff like Pantera, Megadeth, Slayer, and Sepultura, but I didn't really like any of it. The only other band that I really liked was Iron Maiden.
Then one day, by sheer chance, I happened upon Iced Earth's Something Wicked This Way Comes and bought it simply because I liked the cover and song titles. It turned out to be the best music I'd ever heard in my life, by a longshot. At that point I began my real journey.