iOS

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  Universal (iPhone + iPad)

  Rdio

  get itFree

  With Rdio you can listen to your music everywhere — and we do mean everywhere. The service supports not just computers and iOS devices, but also Roku, Sonos, and just about every smartphone platform as part of its $10 monthly Unlimited plan.
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  Universal (iPhone + iPad)

  Spotify

  get itFree

  Spotify makes finding, sharing, and listening to music dead simple, and the service's $10 Premium plan gives you unlimited music on up to 3 mobile devices. One downside: Spotify requires that you use Facebook to log in, rather than using its own accounts.
• 
  Universal (iPhone + iPad)

  Pandora

  get itFree

  Pandora's been doing internet radio for longer than just about anyone, and it shows. Create some stations based on your favorite artists, vote on a few songs, and watch Pandora turn those stations into an amazingly accurate personalized playlist.
• 
  Universal (iPhone + iPad)

  Shazam

  get itFree

  You've got the name of that song on the tip of your tongue, but just can't remember it. Grab your iPhone, fire up Shazam, and in a few beats, you'll get the title, artist, and links to watch it on YouTube or buy it on iTunes. Of course, you'll still slap your forehead when you realize that you really should have known the answer all along.