"Classic albums" where the ones immediately after were too close to call?

Meaning equal quality? Too close to call how? Whether the next was a classic or not?

Fragile = Close to the Edge
Nursery Cryme = Foxtrot
Aqualung = Thick as a Brick

I will try to do this in alphabetical order.

Beatles (Rubber Soul - Revolver)
Bob Dylan (Highway 61 Revisited - Blonde on Blonde)
Genesis (Wind and Wuthering - A Trick of the Tail)
Grateful Dead (From the Mars Hotel - Blues For Allah)
Jethro Tull (Songs From the Wood - Heavy Horses)
King Crimson (Red - Discipline)
Pink Floyd (Wish You Were Here - Animals)
R.E.M. (Lifes Rich Pageant - Document)
Wings (Band on the Run - Venus and Mars)
Yes (Tales From Topographic Oceans - Relayer)

I am sure I could think of others.

You have been very argumentative lately over the most trivial shit.  I spelled Lifes Rich Pageant without an apostrophe this time to try to avoid it.  Come to think of it, there might be one or two other mistakes here but you might as well do the spellcheck yourself.