While I love Spotify as a user experience and definitely plan on using it myself, I'm not bullish on pure music consumption apps as a business. The music labels have unfortunately made it very difficult to get content licenses and even for those who have gotten content licenses, have made it very expensive.

Check out David Pakman's post for more details on how bad the label deals are for most music consumption apps:

http://dpakman.wordpress.com/2008/12/27/invest-in-music-star...

It's not available in the US, and therefore doesn't have much attention here.