Since you are all going into such detail, I think I will to.
Chronological order, as far as I remember.
First off: The Vines - Highly Evolved. I loved The Vines back in the day. I remember downloading Outtathaway from Limewire and then going out a buying the CD the next day. I have since moved onto heavy things.
Secondly: Queens Of The Stone Age - Songs For The Deaf. One of the first albums that I can remember buying with my own money (there was one before that I remember, but I'm not telling what it was). QOTSA is one of my most influential artists.
Thirdly: Nine Inch Nails - The Fragile
. My friend lent me his copy of this, and subsequently got me almost addicted to NIN.
Fourthly: Metallica - ...And Justice For All. While Metallica are not on my Favorite Bands list, this album is the album that got me into metal. A milestone.
Fifthly: Slayer - Every album up to Divine Intervention. Show No Mercy was awesome, Hell Awaits was awesome, Reign In Blood is a classic, South Of Heaven was awesome, Seasons In The Abyss is my favorite album of all time and Divine Intervention is the most evil album I have ever heard.