Fredereich von Schiller, the famous German dramatist, kept a drawer full of rotten apples in his desk. He claimed that the whiff of decaying fruit inspired him to write. Another one of those writers it would have been very difficult indeed to be married to. Although it would be interesting to try the experiment — somebody find some apples and give it a go!
In an interview with the Guardian, novelist T.C. Boyle goes with music, saying:
I always listen to music while writing, so I have shortcuts to iTunes and Sonos on my desktop. I find that the rhythm of whatever piece is currently playing (classical or jazz, primarily John Coltrane, blowing away at this very moment) penetrates some deep place inside of me and helps remind me that writing is a lyrical activity.
This is a highly YMMV point; I need complete silence while I write, otherwise I can’t ‘hear’ my characters.