There was something seriously fucked up about the 80's and as a consquence, we got some of the greatest music of the past century.
The 80's was truly the Epoch of Metal, and it will forever be looked upon as the golden time that spawned bands such as Metallica, Megadeth, Slayer, Kreator, Death, Deicide, Dream Theater, Pantera etc.
The 70's were also quite brilliant, cause of the classics, such as Zeppelin, Maiden, Sabbath, Journey etc.
90's hailed a pretty dry spell for great music, there's only Nirvana, Chilli Peppers, that made it big (britpop doesn't count as music ), but underlying this, the metal scene started to branch out, into more melodic variations, spawning bands such as At The Gates and In Flames.
The 00's so far are looking good for the music I love, but as always, there's a lot of bland shite aswell, such as most Indie/ Emo/ Other Pretentious crap made and packaged for the Urbis crowd.
So overall, the 80's is what did it for me, not only for metal, but for Punk aswell, a lot of really brilliant second generation punk bands arose, or reached their peak here such as Bad Religion, Discharge and The Misfits.
Thats my two cents.