Revolver is the seventh studio album of The Beatles and was released in August of 1966. It is generally considered The Beatles's best album, and one of the best albums of all time. I'm more partial to the ones preceding Revolver, but there are a lot of great tracks on this album.
The finalists are:
"Love You To" by, George Harrison. It really takes the sitar and Eastern influences first used by The Beatles in "Norwegian Wood" to a whole new level.
"She Said She Said". Quite often this one randomly pops into my head. Very trippy lyrics and I love the tempo changes.
"Tomorrow Never Knows". Turn off your mind relax and float downstream. I love the opening lyric. This is probably the song that ushered in the more psychedelic era of '60's music.
But the winner is Paul's "For No One". It's a baroque love song about the end of a relationship. Everyone called Paul the cute one and said he wasn't as deep as the other Beatles (still a criticism of him). But this song had amazing heart and is beautifully composed. You can listen to the studio version here, but here's a great version Paul did after The Beatles.