NepTunes!

Bowtie is a desktop accessory that allows you to see and control your music (iTunes, Spotify, Sonora, or Rdio) with customizable shortcuts, advanced Last.fm support, and hundreds of beautiful themes available to download for free.

[Free fo Mac, $2.99 for iPhone]

CoverSutra gives you a handy and attractive way to control iTunes without ever leaving your current app.See what’s currently playing, pause and resume playback, change songs, and even enjoy your album’s artwork without being interrupted from your work.

TunesArt offers new features for iTunes : display cover art and track information on your desktop (many themes available), get notification on track change, display bezel notifications on play/pause/next/prev, search your iTunes Library, scrobble to Last.fm, display/edit/download lyrics… and more features to discover!

BarTunes allows you to control iTunes from your Mac's menu bar.

Play/Pause and Next/Previous functions for Spotify directly on your Menu Bar!