like many people have said, space, no people, clean working area, comfortable chair, and "white noise." To that, I'd add, a place where I only go to work (except that puts a barrier between me and actually getting *started* on the work - I've been meaning to go to campus Real Soon Now for two hours and counting...) and an area where I can pace and think for such things as transitions in my writing. For "white noise," I have a "no-words" station on Pandora with a mix of techno, dance, classical, and especially Renaissance choral pieces. Oh, and Indian and Middle Eastern music as well. Quite eclectic.