In my opinion, Wish You Were Here is the peak of popular music. Zeppelin IV and Abbey Road are a close second and third.
My quick analysis:
High Point...
WYWH: Wish you Were Here
IV: Stairway to Heaven (i am required by law to say this, although I am partial to Going to California)
Abbey Road: Something
Winner: Draw between Something and Wish You Were Here
Low Point (relatively speaking, of course)...
WYWH: Welcome to the machine
IV: Four Sticks
Abbey Road: Octopus's Garden
Winner: WYWH
Extremely long and Experimental Song:
WYWH: Shine on you crazy diamond
IV: When the levee breaks
Abbey Road: Golden Slumbers medley
Winner: WYWH. Shine on you crazy diamond fucking OWNS.
Album Cover...
WYWH:
IV:
Abbey Road:
Winner: Abbey Road is a classic, but I'd have to give it to WYWH for the burning man.
Overall: Wish You Were Here