It's an impossible question, as others have said, my list would change if I did it again in 10 minutes.
I'm going to do it in 5 decades or else it'd just be 90s britpop.
60s: Abbey Road - The Beatles
70s: Ziggy Stardust - David Bowie
80s: Appetite For Destruction - Guns n Roses
90s: Definitely Maybe - Oasis
00s: Origin Of Symmetry - Muse