SmashTunes lets you control iTunes and Spotify from the menu bar. It displays the currently playing song right on your menu bar along with other information that you choose (like artist, album, duration, rating).
SoundBar is a distraction-free SoundCloud music player right in your menu bar. Just copy/paste a playlist url and play it. No need to create an account.
Synergy gives you total control over your music without interrupting your workflow. It puts small buttons in your menu bar that allows you to navigate your music collection and control iTunes without having to leave your current application.
Whenever a temporary interruption occurs while you’re listening to music, just click the Take Five icon in your menu bar. After 5 minutes (or every other amount of time up to 30 minutes) the audio restarts with a soft fade in.