This was
so difficult.
The only way for me to choose just one album per decade, was by how many times I've listened to them over the years, and which ones are the collecton of songs with the fewest less-brilliant tracks on that I would skip.
Hence Wish You Were Here wins out for me over Dark Side of the Moon, or Ramones, or Never Mind The Bollocks etc. for the 70s, as I never skip any tracks on it - it's perfect from start to finish, especially how it starts & ends.
So if I had to keep only one album from my collection for each category below, and only listen to those 9 albums for the rest of my life, today they would be these:
Best Album of 1960s
Switched-On-Bach - Wendy CarlosBest Album of 1970s
Wish You Were Here - Pink FloydBest Album of 1980s
I Just Can't Stop It - The BeatBest Album of 1990s
The White Room - The KLFBest Album Of 2000's
Black Cherry - GoldfrappBest Album Of 2010's
Group Therapy - Above & BeyondBest Album Of 2020's so far
Ex Machina - MetrikBest Live Album
It's Alive - RamonesBest Album of All Time
Out of the Blue - ELOWhile Wish You Were Here is perfect for all of its 5 tracks, Out of the Blue wins out for me as it's a
double-album of no fewer than
17 superbly written, arranged, performed & produced songs that I can enjoy from start to finish without reaching for the 'skip to next track' button more than once whenever I'm not in the mood for 'The Whale'.
And even though I've heard Mr Blue Sky played on the radio so many (too many) times that I'd gladly never hear it on its own again, when it comes up as the final movement of 'Concerto for a Rainy Day', I always let it play because it's in its perfect context
there.
On another day I'd probably pick Wish You Were Here for its
44 mins of perfection, but I've already chosen it for the 70s, so it's Out of the Blue that gets the nod for the even longer enjoyment I get from its
65 mins (out of 70 mins = 92.86%

) of perfection.