There are a few pretty perfect songs. The ones that break your heart a little bit every time you hear them. And not because of what they remind you of... that's different. These are just so altogether right that it makes you believe a little bit in divine inspiration.
One is Etta James' "At Last."
Another is Rufus Wainwright's cover of "Hallelujah."
I'd put a few others on my list. Tony Bennett's "The Way You Look Tonight." Lennon's "Beautiful Boy." Jackson Browne's "The Pretender." Dire Straits' "Romeo and Juliet."
What's your perfect song?