I might be late on the uptake here - open public beta started in February - but I have to say this is one of the most impressive streaming music apps I've ever used 
It finds pretty much everything mainstream I've chucked at it (although it's missing a lot from the futurepop/EBM/industrial genres), and every song starts playing instantly - no waiting for a buffer whatsoever!
In the music subforum, someone recommended a band I'd never heard of - looked them up on Spotify, listened to the full album, and enjoyed it. No need to listen to samples, or pirate the CD to listen before I buy.
I recommend everyone get a Spotify account - either that or recommend me an even better app!
http://www.spotify.com
It finds pretty much everything mainstream I've chucked at it (although it's missing a lot from the futurepop/EBM/industrial genres), and every song starts playing instantly - no waiting for a buffer whatsoever!
In the music subforum, someone recommended a band I'd never heard of - looked them up on Spotify, listened to the full album, and enjoyed it. No need to listen to samples, or pirate the CD to listen before I buy.
I recommend everyone get a Spotify account - either that or recommend me an even better app!
http://www.spotify.com