Hmmm...

I'd say Demon of the Fall by Opeth becuase it's the song that I finally got really comfortable performing infront of people with.

Either that or Blue Oyster cult's 'don't fear the reaper' becuase it was the first rock i'd ever listened to, I was like 4. After that my brother got me into Sabbath, RATM (back in 92-93 when they were still really really new), SNoop Dogg (please don't shoot me), and from there my interests went into manson, and I was really into him and he mentioned Ministry in his book, so i went and got some ministry, that's when I discovered Skinny Puppy and KMFDM. Of course I was gathering in other stuff at the time, like Fear Factory, The Cure, Neurosis, Nevermore, but it all kinda started with the Cult..and Sabbath I suppose.