60s.
free & avant-garde jazz (later works of John Coltrane is enough to put this decade in front...) like Albert Ayler, Coltrane, Pharaoh Sanders, et al. plus plenty of innovative late 60's rock, like:
King Crimson's debut, Doors' debut, Leonard Cohen's first two albums, Captain Beefheart's Safe as Milk & Trout Mask Replica, Velvet Underground's first two, Neil Young's Everybody Knows This is Nowhere, early Frank Zappa, early Pink Floyd, Van Morrison's Astral Weeks, Tim Buckley's Happy Sad, Bob Dylan's early electric period, Led Zeppelin's first two, Stooges' debut, Pet Sounds, Beatles, etc...
the more I think about it, the more obvious it is that 60s is unmatched. but don't get me wrong, there's been plenty of great music in all decades since

70s is a close second for progressive rock, krautrock & punk.