The "our song" that Katherine and I share is Tear Stained Eye by Kasey Chambers. I can't find an online version, but it's really, really good. Katherine tells me that the best music in the world comes from Austin.
Another favorite of ours is Kenny Chesney's Anything But Mine. We have an Austin-style cover of this song which is superior -- more hauntingly romantic -- than the original.
What's your "our song"?