They're my favourite band! My favourite Beatle is George; I adore his solo work as well.
(If "The Ballad of Sir Frankie Crisp (Let It Roll)" isn't a perfect song with a perfect melody I don't know what is...)
I don't think I could pick an absolute favourite Beatle song, but I tend to lean towards George's stuff. But I still love the other ones work as well, of course! Some that come to mind..."Here Comes The Sun", "While My Guitar Gently Weeps" "I Want To Tell You", "And I Love Her", "I Saw Her Standing There", "Rain", "Ticket to Ride", "Michelle", "If I Needed Someone" well the list is getting too long so I'll stop.