I thought this was an interesting website: Writers Houses, where A.N. Devers chronicles her visits to (you guessed it) famous writers' houses. You can find out more about her reasons on the website, where you can look up houses by author, state, etc.
Fun and interesting.
And I chose this house for me to write in when I'm rich and famous, since we're on the topic and all. I hear Tuscany is the best place to write.