60's : Early Pink Floyd and Led Zeppelin. Masters of classical rock like the Beatles or Stones, Clapton, Hendrix...
70's : Masterpieces by Floyd (Dark Side Of The Moon, Wish You Were Here...), Zeppelin, Sabbath, early Judas Priest, Rush and Yes just to name a few.
80's : Major releases from Maiden, Rush, Queensrÿche, Priest, Helloween and Metallica.
90's : Good albums from Maiden and Helloween too. Bands like Strato, Symphony X or Dream Theater followed their way through this decade. Late 90's appeared Rhapsody, Nightwish or Sonata.
2000's : All major bands from the 90's continued their way.
Feel free to add some other major bands and give you opinion

For me I think it is the 80's for sure, with all the classics by Maiden and Rÿche especially. Closely followed by the 70's.