Even though I'm in the "classic vinyl' age group with the majority of posters on this thread, I'm going to go a little more recent and say Michael Morales "Who Do You Give Your Love To?", and Thomas Dolby's "She Blinded Me With Science" both stand the test of a little less time. Back in my becoming an audiophile days, "Baby, Now That I Found You" by the Foundations, and "Red Rubber Ball" by The Cyrkle always made me reach for the volume knob. In the surf genre, "New York's a Lonely Town" by The Trade Winds gets a nod as well.
I've had to give a thumbs up to pretty much every tune listed on this thread so far. We got to grow up during a time when music itself was growing up. Being able to say, "I remember when that song came out on the AM radio" puts us in an especially privileged group of music lovers, because in those pre MTV days, the AM radio station DJ's were ultimately the ones who decided which songs were hits. Air time was expensive, and they wouldn't waste it on songs that didn't have what it took to stay on the charts, or even songs that ran over a certain time limit. When Phil Spector produced The Righteous Brothers "You've Lost That Loving Feeling", a song that ran almost four minutes, he knew it was a chart topper. He also knew that most stations wouldn't play a song that long, so he deliberately misprinted the label time as 3:05 to make sure it got the air time it deserved. By the time the DJ's figured out the scam, it was too big of a hit to stop playing it. That's always been one of my favorite stories from the halcyon days of rock music. I'm glad I got to be a part of that special era.