I don't have many desktop apps installed; one of the few I have is Spotify.
How will Chrome OS provide music for its users?
I don't think they've announced any solid details so this is pure speculation, but if you listen to the rumour mill they'll have a cloud based 'hard drive' where you can store music purchased from Google themselves and listen back via a streaming service.
I think they'll offer quite a big cloud drive, which will probably be included in the price - like how Apple charge more for the 64GB iPad than the 32GB, Google may offer a staggered cloud drive correlating to a price. On this cloud drive I think it'll be possible to store photos, music, video etc.
I think it'll be very interesting to see what they offer and if it succeeds I believe it will be a game changer for a lot of IT products.
I can see Spotify releasing a web based client. Spotify uses P2P to distribute data, and with methods for P2P transfer in the HTML5 spec it is a possibility.