@parapaul - it sounds fantastic that you have migrated your life to the cloud. Call me old-fashioned, but I am not quite ready for that. Have seen too many black spots (London tube?) for me to have the confidence that the cloud will be available on my phone whenever. And I do know that you can specify to make music tracks (and other data) available offline, but that needs me to (i) either specify in advance what music I want to be available offline or (ii) have enough storage in my phone, which makes the whole thing moot. I like to have my entire collection of ~50GB available to hand, so I can listen to whatever I want whenever I want.
If the cloud was the only option in this world, I might be able to live with these compromises. But why bother when the nexus 4 is not the only party in town?