I'm anti-headphone, but my wife has a set of bike speakers for when we do longer rides. It's kinda fun and passers-by get a kick out of it. When I'm riding solo, I tend to prefer silence, although on one particularly tough climb out in the middle of nowhere, I put my phone on speaker and listened to some music because it was dead quiet and I had 7 miles/2k feet of climbing in front of me.