Ahh, like this kind of threads, sweet nostalgia!
Well, in January 1990 a friend lended me a tape with Iron Maiden's Seventh Son Of A Seventh Son album, I then taped all his Maiden stuff, then I went on to Metallica and Slayer soon followed, I still remember hearing Reign In Blood the first time and going, what the fuck is this, I could hardly believe music like that existed! This just ain't music, the guy's just screaming!
But soon I got used to it and started getting into some Death Metal as well, Obituary, Death etc. In 1992 I bought my first CD-player and started buying my own CD's, resulting in a collection that'll reach the 1000 mark quite soon I think...