The Fabs, 1966. Pretty much my favorite track from Revolver -- "And Your Bird Can Sing."
Just the guitars, bass and drums.
HOW COME I DID NOT GET THE MEMO ON THIS ONE?????
Seriously, I'm well aware that there is no Greatest Rock Band of All Time any more than there is a Greatest Novel or Greatest Painting of All Time.
That said, any bunch that could make a noise that brilliant before the vocals were even appended has got to be in serious contention for the title.