In My life?
Definitely the Abbey Road Medley. However, if I had to pick one song, I’d go with “Hey Bulldog.” Love that piano and the growl.
I’d rather die.
Not a song title, I just love their music. Anyway, you can’t take them away as I can hear them in my head. I’m amazed nobody has mentioned Yesterday yet.
Something.
Never went for the ballady stuff much, and most of what they did before '66 or so is so familiar that I never have to hear it again, and so lightweight that I don’t really want to hear it again, nevertheless…And Your Bird Can Sing. Two minutes of pure crystalline power pop. Can’t concieve of ever getting tired of the guitar riff or the harmonies.
Let It Be
Yesterday, because that is the day that I could listen to all the Beatles songs.
Yup.
Oh man. What a scary premise! Thank God it’ll never happen as long as I’ve got the entire canon lodged in my brain, but still…
This may be an odd choice but I think I’d go with You Can’t Do That. It just makes me happy as heck and it’s a great song to sing along to (both melody and the background vocals).
Or maybe “I’ll Follow the Sun.” Or “Here Comes the Sun.” Or “Taxman.” Or “Penny Lane.” Or and or and or…
(Actually my favorite song is “She’s Leaving Home” but I think it’d be too depressing to make that the only Beatles song one hears ever again.)
I’d pick “Something.”
“Hey Bulldog”
Why are you looking at me like that?
“Eleanor Rigby”
Although I would miss “I’m Looking Through You” terribly.
I considered this, along with *Lady Madonna. *But I finally went in the opposite direction, and decided on Let It Be.
Blackbird.
That was the one I came here to post.
When George got it right, he really got it right.
Oh, crap, off the top of my head I was going to say “Eleanor Rigby,” but “While My Guitar Gently Weeps” is the Beatles too, isn’t it? Yeah, I’m with Frank. So long, “Let it Be,” “Yellow Submarine,” and “Come Together.” 
ping-pong balls marked “here there everywhere”, “i will”, and “fool on the hill” are tumbling in the lotto casing. which pops out: HERE, THERE, EVERYWHERE!
She’s Leaving Home
I’d be content to not hear the Beatles again, but the song I’d want to hear (if I had to hear one) is Across the Universe.