These songs came to my mind immediately...
I Wanna Cry - Paul singing the blues and playing some tasty lead guitar.
I'll Give You A Ring - A lovely song featuring Paul on piano and showing off his fun play with words.
Rainclouds - A beautiful song written with Denny Laine.
My Best Friend - A song Paul played back when he first started playing live with Wings. Very nice.
And there are many more....