What are yours?
This list, from Inky Fool, has been compiled by the number of hits each line receives when it is fed into Google. To my mind that means that it isn’t accurate because there is no way of knowing or calculating the lines from poetry the man in the street uses everyday. I’d be surprised if it wasn’t a line from Shakespeare, given that he coined a remarkably number of the phrases that we use everyday. But as M H Forsyth says in the piece, Google is the best we’ve got!
The Guardian has a comment on it and below, is the breakdown in graphic form. Click each image to enlarge.
Tears in the Fence 
I am amazed to see Alexander Pope at number on and W.E. Henley at number three beating Shakespeare at four. A fascinating survey!