I admit it's a tough choice and I'm still not sure about my choices. But generally, their earlier stuff is among my favorites. And oddly, some of them are songs Lennon & McCartney didn't write. But the way they performed the songs composed by others make them special to me. 

My Top 5 Beatle tunes:

1) Rock & Roll Music
2) Eleanor Rigby
3) Hard Day's Night
4) Please Mr. Postman
5) And Your Bird Can Swing

Runner ups: I'll Cry Instead and I'll Follow The Sun

Yes, that's a pretty eclectic list and I'm pretty sure it wouldn't match anyone else's. But if I had to pick just 5, those would be the ones.