Steven Brust worked as a programmer before he was a full time novelist, according to his son, who is also a programmer.
Another example: Vernor Vinge (sci fi author, and a former math and CS professor at San Diego State) uses emacs [http://www.norwescon.org/archives/norwescon33/vingeinterview...]
Yet another example would be Neal Stephenson:
"I use emacs, which might be thought of as a thermonuclear word processor."
- In the Beginning was the Command Line http://www.cryptonomicon.com/beginning.html
There was a Salon article about people still using XyWrite[1]. As mentioned in the post, GRRM is one of the people[2] still using WordStar. I know that Steven Brust is using Emacs[3].
[1]: http://www.salon.com/21st/feature/1998/08/25feature.html/
[2]: http://www.sfwriter.com/wordstar.htm
[3]: from the front matter of http://dreamcafe.com/firefly.html