After playing around with Spotify over the weekend, I REALLY like it. If you don't know what it is, think of a radio station where you can pick any song they have and play it when you want to hear it as much as you like. From a UI standpoint, it's iTunes without purchasing the song. Downside is that the mobile platform is only for paying subscribers, but as an application to use while I'm programming, it's awesome.

The UI is easily navigable, since it's set up like iTunes. Search works really well.

The sound quality is much better than Pandora. In Pandora, the low frequencies are sometimes thin, in Spotify bass booms through the headphones like it should and the sound is full, rich, and wonderful.

So, Spotify is everything I had heard it was and I'm stoked to be using it in the USA!