Ever since I was in high school I've found that there's certain music I can have on in the background while I'm working, and certain music that, no matter how much I love it normally, completely shuts my brain down to any kind of rational thought.
I'm thinking about this in the upstairs room in my Toronto apartment, in part because the CDs are still in stacks on the floor--it's a media fortress, actually, with stacks of books that have to be stepped over on the other side of the desk.
So what can I work to? Mostly, it seems, music I formed some kind of attachment to before I started college. The Smiths, for some reason, not only seem to allow me to work but somehow allow me to work faster. R.E.M.: yes, but only up through Fables of the Reconstruction. Bach: yes, pretty much anything, although the Glenn Gould recording of The Well-Tempered Clavier seems to work much better than the cling-clangy Brandenburgs. Beethoven: symphonies yes, string quartets no. No Doubt: definitely not.
I'm not sure that I can write poetry, incidentally, to any background noise other than the screeching of an elevated train.