Awesome topic! This is a conversation I often have with my friends.
Guns N Roses - Appetite for destruction
Metallica - kill em all
Beastie boys - license to ill
Weezer - blue album
Sublime - sublime
Wu tang clan - enter the 36 chambers
Eminem - the Marshall mathers lp
Foo fighters - wasting light
Slipknot - Iowa
Eazy E - eternal e
Mudvayne - L.D. 50
Nirvana - nevermind
Marilyn Manson - antichrist superstar
In the era of MP3 players it's less and less common to find new albums that you actually want to hear front to back but this is my list of essentials.