I hope someone was cynical enough to have already included "What's Love Got To Do With It" by Tina Turner, or "Love Is Just a Four Letter Word" by Bob Dylan.
But I'm a sentimental cynic so I would also vote for "Have I Told You Lately That I Love You" by Van Morrison (mentioned above by Digsmithd) and add "Time After Time" especially as done by Miles Davis or Cindy Lauper. These two songs seem to apply not only to romantic love but also to the love and affection of family and friendship. Those are things even a cynic can get behind.
JPO
