I don't know about you, but I need to listen to music while I write and I'm constantly on the lookout for new bands and musicians that I feel like I write well to.
There is no one type of music that works best and sometimes I find that different styles work for different types of writing. Certain classical pieces for certain situations, certain jazz pieces (Kind of Blue, eh people?) for others, folk for some, etc.
And then there's the video of Arcade Fire below. Whenever I feel down and beaten up by writing and the business, it happens to everyone, I watch this and feel much, much better. Arcade Fire is so authentic and almost pure in its expression of creativity and enjoyment of what they do, how could anyone not be inspired.
Three rejections in one day and one of them is nasty, watch this. Stuck in your novel and can't find the way forward and everything you write feels like shit, watch this. Just feeling like your not a writer and want to toss the whole thing, watch this.