It's more than possible to include extra information in each block (Darkcoin recently did exactly this to store their Master Node votes) - perhaps we could build a system which allows individuals to submit a single file by concensus per block, as groggin mentioned perhaps utilising the Bittorrent protocol. These tracks could then be streamed from all around the world via magnet/DHT once they had reached a certain level of propagation. The bandwidth requirements of the protocol would be marginally bigger, but no more than running a music player like Spotify constantly, and wouldn't have any kind of centralised server requirements.

At 1 minute block times, this would allow for a maximum 1440 new submissions every day. Is that enough?

People could perhaps even only stream their own "favourites" list or something, encouraging people to produce music that others enjoy, as they wouldn't have any incentive to produce or submit garbage because it would never propagate, and thus would consistently waste their own bandwidth. It would also further incentivise staking, as having your wallet open would be a necessity while initially broadcasting any new track. It'd be like running your own, totally decentralised radio station!

Starting to feel like we might be getting somewhere :-) Definitely feeling the excitement vibe!

EDIT: Another thought: To offset the inflation of PoS, and to de-incentivise spamming the network with garbage, we could introduce collateral payments to make a submission, thus to spam the network would be a considerable expense.