I've had a small problem with orgmode and auctex.  Follwing the auctex
quickstart I added the following to my .emacs

(setq-default TeX-master nil)

and then from the orgmode FAQ to setup reftex in orgmode I added the
following

(defun org-mode-reftex-setup ()
  (load-library "reftex")
  (and (buffer-file-name)
       (file-exists-p (buffer-file-name))
       (reftex-parse-all))
  (define-key org-mode-map (kbd "C-c )") 'reftex-citation))
(add-hook 'org-mode-hook 'org-mode-reftex-setup)

With both of these, whenever I opened an org file I was asked to name the
master file.  If I comment out the setq-default I don't get the behaviour I
would like with mulitfile tex files.  My solution was to change

(setq-default TeX-master nil)

to

(add-hook 'TeX-mode-hook (lambda ()
               (setq-default TeX-master nil)))

I then appear to get the behaviour I desire.  Is this a good way to do
this?  If so I might add it to the FAQ.

Cheers
Chris.