Do you listen to music or streaming radio while you work? I find I'm much more efficient when there's some music in the background or maybe a podcast if I find something interesting online or at the iTunes store. But one thing that breaks my concentration is the need to continually go back to iTunes to make new selections. To keep the distractions at a minimum, I like to set up my music or podcasts beforehand and get to work.
As a software reviews writer, I spend a lot of time using a word processor with my hands on the keyboard. So when the music I'm listening to changes to something I don't like or when a podcast gets a little too distracting, the last thing I want to do is leave my word processor and search around on iTunes. Fortunately there's a program that lets me control iTunes using hot keys.
Synergy (Leopard) is a long-time favorite of mine for quickly switching songs in iTunes. It places some basic controls--like play, pause, and skip--in the menu bar for convenience, but where Synergy really shines is in its use of hot keys. Without touching the mouse, I can quickly adjust volume, skip tracks in either direction, shuffle playlists, rate songs, and even quickly bring up iTunes if I absolutely must choose something different. One of the best things about Synergy is how it elegantly brings up a floating window at the beginning of every song with artist name, track information, and album art so I always know what's playing.
The linked version of Synergy above will only work with Mac OS X 10.5 Leopard, but you can get Synergy for older Mac OS versions here. Whatever your operating system, Synergy makes listening to music while you work much more convenient and, at less than 10 bucks to register, it's worth every penny.