BarTunes lets you quickly view an album artwork, rate it, play/pause a track, skip forward or jump back through your music, and much more.
BarTunes enables you to perform a bunch of actions on your tracks without asking you to actually bring up the iTunes window, for each one of them
NOTE: The BarTunes can only be purchased via the Mac App Store (the buy link redirects you to its App Store page). To purchase/download applications via the App Store an Apple account is required.