I have a playlist called Tasteless Rap on Spotify that helps me focus. Solid beats, lyrics that are pretty easy to memorize (and thus not get too caught up in), and fun. I've got it arranged into a pretty good ebb and flow of energy, so I don't get worn out halfway through. I also second @gadders' birdsong comment: it's quite lovely, especially with coffee/tea. Which reminds me, Coffitivity has been excellent for tuning out the distractions of our open plan office (it's not fully open, but the room I'm in has 4 other people with no blockage of sound or sight lines and is quite busy).