Well I absolutely LOVE Eric Clapton so it has to be Wonderful Tonight.  It speaks of his great love and there is just no other woman for him.  It always brings a tear to my eye.  Oh my gosh I heard him perform this in concert and I was one hot mess after he finished.  Listen to his words of love and his guitar speaks volumes too.  He pours out his love thru his guitar:

http://www.youtube.com/watch?v=vUSzL2leaFM

However I have a number 2 choice too.  Bryan Adams "(Everything I Do) I Do It For You"

Michelle your selection is beautiful.  I got a lump in my throat listening to it.