Definitely not the 90s.

60's and 70's for sure. 60's for the experimentation and creativity and opening a lot of ideas up, and the 70's for mastering a lot of those ideas- and punk raawk.

70s for proggressive rock, Blues Rock, and Funk/Soul.

The 80s for variety.

90s for Alternative Rock/Metal.

Today

Early '90s.

1.) Grunge helped to bring Alternative Rock more mainstream attention. Pixies for the win!

2.) There were still some decent Hard Rock bands around, like Van Halen with 'for unlawful carnal knowledge'. Eddie could still play guitar!

3.) There was some good Heavy Metal too with Metallicas 'black album', Megadeth and even Ozzy was not yet a wanker during this time period.

70s

mostly for funk, proto-metal and punk

90s and now

1970-75. Mostly for the Art-rock and Prog Rock stuff. Plus a lot of the great bands that originated from the sixties reached their peak around here. (The Stones, The Who, Pink Floyd, Led Zep, Beatles' solo careers etc.)

that's probably my 2nd fave VH after the debut

65 to 75 is the undisputed champ. Hendrix Zep Floyd Sabbath Purple....I mean come on