able to not just stream, but have most of my music library on my phone. That's the thing - when you're using a combination of streaming from a service like Beats Music or Spotify and using your own purchased or downloaded music, your library doesn't need to be as large. You can just use the HD memory for the stuff that is rare, or was never released, plus major release stuff that you listen to often and will want to listen to even when you don't have wifi or a cell signal available to stream. Then use the streaming service for the rest.

128gb should be PLENTY for me using that, plus my apps, pictures, etc.