I have absolutely no downloaded music on my iPhone 5. Rather, I have a Rdio subscription and use that to stream songs and albums to and from work. That way, I don't have to worry about running out of space on my phone. All my downloaded music is on my iPod Touch which I currently keep at home to listen with my Bose Sounddock.
I think having a Spotify/Rdio, etc. subscription with the app on your phone is great. Especially for those of us who have a lot of downloaded music but only have 16GB iPhone's.