I can't really think of any I especially like for being love songs.

Two of us, and
For No One are good McCartney love tunes. Honey Pie.

Dylan's I Want You, and the one that starts My Love she speaks like silence...

Khandu, I can't think what Tull song "Love Story" is, but I love that a guy's wife wrote the lyric to Aqualung about him, and he wrote Cross-eyed Mary about her. I really think that's lovely, somehow. Also liked Wond'ring Aloud.

   Did someone already mention Romeo and Juliet? Mark Knopfler.

   John Hiatt's Learning How To Love You.

   Simon and Garfunkel, Ccelia. I love sluts, I guess. Among my slutty friends, when I was a kid, Meatloaf's 2 Out Of 3 Ain't Bad was considered the greatest song ever written. That still breaks my heart.

   Lucinda Williams, several songs.

   For some reason I get a kick out of Frankie Lymon and the Teenagers' Why Do Fools Fall In Love.

Red River Valley. Come and sit by my side if you love me--that's a great first line.