"Freebird" by Lynyrd Skynyrd - Especially during the Guitar Solo. Seriously, during the singing, score foreplay, at the solo, GO TO TOWN.
"I Won't Hold you Back" by Toto - Awesome romancing song, and it was used quite tastefully in an Italian movie which had some pretty odd Folgers Coffee kind of look to it. Still, a great song.
"Hallelujah" by Leonard Cohen - After seeing the Watchmen pull it off quite well, I'd try it once.
"Twilight" by The Electric Light Orchestra - If I had been high, the song might have been grand, but still, it's a peaceful, easy song, for LOVE.
EDIT: I meant "Starlight" by E.L.O. Big mistake on my part.
"My Love" by Paul McCartney - Different? probably. Great? Yes.
"Pleasure (Pleasure)" By Bang Camaro. It's not just a great Rock Band song, it could definitely be good for some lovin'.
and of course,
"Feel Like Makin' Love" By Bad Company. Bonus Points if you can time yourself to the guitar part.
"Duh-Duh, DAAA! Duh-Duh, DAAA! Feel Like Makin' Love."