[chewbranca]

Silence is great, but sometimes silence can be, well, too silent. I bounce back and forth between coffee shops and my home office, because sometimes I want to sit at home in silence or listen to music, and othertimes sitting at a coffee shop with a lot of ambient noise helps me get into the zone. Something about having a lot of random noise around that I don't care about listening too helps me concentrate.

[rjprins]

http://www.simplynoise.com and/or http://www.rainymood.com

[limmeau]

Or more customizable: http://boodler.org/

[larrywright]

When I need to focus, I listen to music, but it has to be instrumental. Jazz, classical, even ambient (Brian Eno's "Music for Airports" is my go-to album for focusing). I've also used noise generators, like Ambience for the iPhone, or Bloom (also by Brian Eno).

I have a real hard time getting focused unless there is some sort of music playing.

[frossie]

sometimes I want to sit at home in silence or listen to music, and othertimes sitting at a coffee shop with a lot of ambient noise helps me get into the zone

Sounds like a DIY version of the Hawthorne effect - you just need to occasionally change your environment, it doesn't matter what to, because change itself is stimulating.