In the last 30 days, I've easily discovered more great new music than I have in the last decade, and have listened to the iTunes equivalent of at least $700 in music for the cost of a CD.
I'm talking about Rdio, a streaming music service that strikes me as a lot more useful than others that have been around longer. I'm not sure its the best out there in classic terms—I've heard that other services have better libraries. But I do love it for a few big reasons. Rdio's gone out of its way to put itself on more platforms than any other streaming service I've ever seen. It's on android, iphone, blackberry, the web, has a desktop client and even works with my favorite home audio multi-room system, Sonos.