Some replies to individuals:
Bruno: I'd say between AHDN, Help and Rubber Soul.
In Revolver they started to work separately, like Paul with Eleanor Rigby and John with Tomorrow Never Knows E Rigby had huge group input (except for playing). Tomorrow had Paul "playing" the tape loops and Ringo's drumming is tops!
Frighty: Please Please Me. Their opening album and the one with all the classic Beatles harmonies. Definitely sounded like a unit at this point. They were a unit, yes, but other albums show them definitely more together; Ringo was still new. And ... er... harmonies? All the classic harmonies?? Ahem, all their albums are filled with their harmony singing! That can't be the criterion!
Number 14: I would say please please me too. This is when lennon and mccartney worked together a lot. none of their later albums thats for sure. The Fabs were more than L and McC working together.
Frighty again: But that's (ie PPM) when they had all the Beatles harmonies with the whole group singing a lot of the songs, and even RINGO sung a song (though it was Boys, he still had a feature). People are saying Revolver and such, but those show a lot of individual works (Paul's goal must have been to use as little of the Beatles as possible in that album). Ringo had a song on almost every album, so that's irrelevant. And that statement about Paul's goal on Revolver is ridiculous.