IMO, "Revolver" is their best album.
As for songs, I can't pick a favorite, but some of their best (IMO) include:
Hey Jude
The Ballad of John & Yoko
Here There and Everywhere
Yellow Submarine
Tomorrow Never Knows
I Should Have Known Better
Ob-La-Di-Ob-La-Da
I Am the Walrus
Old Brown Shoe
Get Back
Don't Let Me Down
Paperback Writer
Rain
I'm Looking Through You
I Feel Fine
She's a Woman
Strawberry Fields Forever
Penny Lane
Ticket to Ride
I Call Your Name
She Loves You
I Want To Hold Your Hand
Day Tripper
We Can Work It Out
Come Together
I Want You (She's So Heavy)
Let It Be
One After 909
Revolution #9 - pretty nifty!
While My Guitar Gently Weeps
I could go on and on...