"Easy" you might say .... but then think again. As there had already been a few answers I had a brief inclination to say something different. I toyed with Appetite For Destruction, as that was the album that kick-started things for me and moved me away from Metallica and Anthrax, but as good as it is it's not THE album. Too many flaws, particularly much of side two.
Soho Roses nearly got a look in for 'The Third And Final Insult', the album that my band at the time attempted to imitate (and almost got there in that we apparently sounded like the Buzzcocks). Then there's the Hollywood Brats - I can still remember my excitement when I first got that LP home and on my turntable.
But in the end it came down to the debut album by The New York Dolls. It wins almost by virtue of the opening chord and cymbal crash on Personality Crisis
Voice your comments and nominations here.