I break music into two categories.
One, the kind that gets moves me like Lady Gaga, Shinedown, Nickelback, and Daughtry. Treadmill music actually.
Two, a playlist I named, My Writing Music
For writing, I need instrumental in various tempos according to what my characters are doing at the time.
In the gentle scenes, the oddly contrasting soundtracks from True Blood or Pride and Prejudice help me see the MC weep. Or imagine the kiss.
For combat/fight scenes, high drama or experiencing great fear, I go with 30 Seconds to Mars.
Their album, This is War, helps me envision the hall where swordplay breaks out. When the wizard raises his arms and calls down Hellfire. Or as my MC dies by the hand of her foe.
Plus it drowns out the TV when the hubby is watching ESPN.