Infigroove is a music streaming service that let you listen and watch milions of songs across the world. It's legal, free and without any ads ! Enjoy a magical journey with the best albums and interact with the community to share your favorites songs.
I found this interesting service that uses YouTube for streaming audio and video and works via web (its creators are working on the app development).
Wefre does not have advertising and it uses YouTube for songs streaming. By keeping the content locked by region, it (at least for now) is not being classified as illegal.
Looks like they have a Kickstarter for their app development; this could be interesting.
While last.fm runs YouTube behind their radio stations, you can't curate/save playlists. And then there are sites like YouTunes which never really developed fully. I hope this works out for them.
Tint & Shade Generator