My guitar teacher lent me a tape of Passion & Warfare by Steve Vai. I was blown away by how much better this guitar music is than the crap i was listening to then (Silverchair, Everclear, Nirvana, you get the point)
I then got into Satch, then DT, then Yngwie and power metal (which i despise now) , then SyX and progmetal, then Opeth and Death metal, now all this jazz and fusion.
So P&W did have a major impact of my life, not only because of its 'ownlyness', but also the world of music that it introduced me to.