I feel like there are a lot of good answers to this. For people who never got into rock, there are some songs like Achilles Last Stand which are just amazing. Then there are some Dylan songs that still get me 1000 listens later. Something I've recently discovered (and I believe Raptor's brought up in here) is Jazz. You simply can't say this isn't amazing:
http://youtube.com/watch?v=oHg5SJYRHA0