I also cannot name just one... But here are some favorites, in no order:

Something
Eleanor Rigby
Come Together
I am the Walrus
Here Comes the Sun
While My Guitar Gently Weaps
A Day in the Life

I think an easier question would be "Favorite Beatles Album?"... Mine is arguably Sgt. Pepper's Lonely Hearts Club Band

"Somebody told me when the bomb hits, everybody in a two mile radius will be instantly sublimated, but if you lay face down on the ground for some time, avoiding the residual ripples of heat, you might survive, permanently fucked up and twisted like you're always underwater refracted. But if you do go gas, there's nothing you can do if the air that was once you is mingled and mashed with the kicked up molecules of the enemy's former body. Big-kid-tested, motherf--ker approved."