Google Play Music allows you to keep up to 20,000 of your favorite songs in the cloud.
outcoldplayer (former gMusicW) is an unofficial Windows 8 client for Google Play Music. Main features are: playing music in background, playlists management, 5 starts rating system for songs, Last.fm Scrobbling (enable it in application settings, "accounts" page), offline listening.
You need to have a Google Play Music account to use this application.
Please vote for features you want to see in next version of outcoldplayer on https://outcoldplayer.uservoice.com/.
If you have any problems with this application check our knowledge base http://outcoldplayer.uservoice.com/knowledgebase
And follow http://twitter.com/outcoldplayer to know about all our future plans.