I listen to a lot of music while I work and to be honest I tend to prefer more easy going stuff.
I am a programmer and when I'm trying to think about problems having background music allows me to concentrate better than loud tunes with loads of distortion.
Oddly I can concentrate well when listening to really involved tunes, just metal tends to sap my ability to concentrate!
When I work I generally listen to stuff like Frank Gambale, Allan Holdsworth, Larry Carlton, Flecktones, Greg Howe, Jeff Healey (mainly the jazz stuff) and Weather Report.
Bands that don't help me concentrate are Animals as Leaders, Meshuggah, Alestorm, Periphery and Tool.
I love all these bands btw, that's why I listed them.
I am a huge Tool and Periphery fan!
although, when I am working, I listen to ambiental music
concentration needs different kinds of fueling in order to go at full power
you are very right. Although, I could not listen to jazz-fusion and do smth else in the same time..that stuff makes me focus on it entirely!