Mac: We've seen a variety of menu bar apps for controlling iTunes, Spotify, and Rdio, but for whatever reason they don't seem to stay updated and working for long. Plaaying's a new app that gives you control over your music player and should continue working because of its custom album artwork system.
At its core, Plaaying is a tool for controlling iTunes, Spotify, or Rdio from your menu bar. It's also a great way to quickly glance at the currently playing track. Beyond that, Plaaying has tools for sharing what you're listening to over Twitter, as well as special intermission modes that automatically stop and start playing your music based on whether you answer a FaceTime call, or based on a timer. You also get plenty of keyboard shortcuts, so you can easily control how Plaaying works.