Well, I am sure the beatles would probably rank highest in a best album ever contest that was judged with critics and took into account virtosity, popularity, staying-power, and the first to last song quality, but they are not my pick. They are good, but they are not MY music. They are my parents' music. They don't hold the same emotional attachment as some other bands.
Here are MY favorites...and I am only listing contemporary music, as it is in a totally different league than classical:
Radiohead -- The Bends. (I agree that OK computer is very close, except for fitter happier, and I don't really like electioneering either...) Also, the My Iron Lung EP which includes the Bends's b-sides which were as good as any other album I have ever heard. Taken to together, they would certainly be the best album of all time in my mind...
Tortoise: TNT
Nick Drake: Pink Moon
Kelly Joe Phelps: Shine Eyed Mister Zen
Jim O'Rourke: Halway to a Threeway
Stereolab: Dots and Loops
Cake: Fashion Nugget
Those are the albums that have the most emotional impact for me -- they take me to the place I was when I first heard them, which I think is on of the most important functions that music can have.
Pearl Jam's: Ten is also excellent, as was Led Zeppelin Three. 1-4 are hard to separate, but I think I like three the best...mostly because of Tangerine and Gallow's Pole...