At Last, Let's Stay Together, Unforgettable, Just Like Heaven, The Long and Winding Road, Both Sides Now (although I find that more of a heartbreak song really, probably because of Love Actually associations
)...
more contemporary... ermm... Amy's "Love is a Losing Game"
Bloc Party's "I Still Remember", Yeah Yeah Yeahs' "Maps", Regina Spektor's "Samson"...