I'm out of step with most in that I don't like III all that much. The big fan faves Gallows Pole and Since I've Been Loving You I just don't like very much! The only top tier tracks for me are Immigrant Song and maybe That's The Way, the rest is just okay.
In The Evening is okay but feels a bit half baked and Plant sounds like shit on it (that 50's reverb effect he was into at the time *never* works). All Of My Love comes close to being left off actually, along with LMM.
Most of Coda was in consideration and probably belongs on there. I also thought about Sick Again which is another PG track that starts out great but loses its way.