My dad collects a lot of 50-60s era vinyl, so even as a little kid I heard tons of rockabilly, doo-wop, R&B, blues, etc. As a teenager in the late 80s I got into some glam metal stuff like Danger Danger and some rock-metal like AC/DC, Bonfire, and The Cult.
The album that got me into the heavier stuff was Overkill's 'The Years of Decay'. The first 3 tracks on that- 'Time to Kill', 'Elimination', and 'I Hate'- became instant favorites. Here was a band that wasn't interested in getting radio airplay or having a hit video. I think being exposed to my dad's music gave me an appreciation for these traits, since so many of the great blues, rockabilly, etc artists were small-time, obscure groups; at most they had maybe 1 hit each, but they recorded lots of great music that got overlooked. The same seemed true with Metal. With Overkill, here was a great band playing music that was heavy and uncompromising, never bound to get any mainstream attention, and I loved it!
Song-wise, one that made a HUGE impression on me was Helloween's 'I'm Alive'. I got one of those generic gas station cassette compilations called 'thrash Attack!' because it had several heavier bands on it that I hadn't heard yet, including Nuclear Assault, Death Angel, Megadeth, Anthrax, Slayer, Savatage, and others. It was a great comp- I still have that tape- but THE song for me was the Helloween track. I had never heard any power metal before, and it blew me away! I memorized that song- every word, beat, note. Living out in the sticks, it was a few months before I made it to a town big enough to have Helloween records in the local record store, but I snapped up 'Keepers pt 1' and it's been my favorite album ever since.
One of my best friends in college also cites 'I'm Alive' as having a profound impact on his life. Apparently as a teen he was running with some pretty racist punk guys- skinhead types I guess. He always said that Helloween really opened his eyes b/c it was music that was heavy but also Happy-sounding, and 'I'm Alive' helped steer him away from being a hateful, racist kind of person. I like to cite that story when people tell me that heavy metal is nothing but meaningless noise
"I'm sorry Sam, we had real chemistry. But like a monkey on the sun, our love was too hot to live"
-Becky
At least my early metal self would have been proud of me still carrying the torch! I wonder what your past self would have said to you, nowadays, that the half of your collection consists of guys dressed in pink!! 
