I included a few of these writers' rooms in an Omnibus post a few months ago. It turns out the Guardian has turned this into a feature now, with even more writers included. A few favorites:
Jonathan Safran Foer (although using a picture of the NYPL is really cheating)
Colm Toibin (Blogger doesn't like my ASCII accented characters - very sorry, Mr. Toibin)
A.L. Kennedy (what is it with all the red walls?)
Looking at all these pictures, one thing is clear: I need to get myself a desk.