To me it is not just a song,it is more about the voice of a singer and the lyrics,then the music,too.
Most songs by Whitney Houston(I will always love you,Didn't we almost have it all,one moment in time,greatest love of al etc.),Leona Lewis(Better in time...),Mariah Carey(Hero,can't live if living is without you,endless love....),Tina Turner(her voice is so great,can't quote a single song),Kelly Clarkson(because of you...),Giorgia(most of her slow songs),Sarah Brightman("nessun dorma" to quote one...),Maria Callas(Casta Diva,Amami Alfredo,Vissi d'arte...vissi d'amore),Celine Dion,Dionne Warwick(what friends are for...) but one of the most moving is "dancing" by Elisa!
I could say all of my "slow songs" part in my I-Pod
.